Scrap event-based approach for refreshing grains

The call to refresh_modules() in saltutil.refresh_grains was resulting
in a race condition with the event I added to refresh the grains. This
meant that, even though self.opts['grains'] was being changed by the new
event, before that process could finish the module refresh was itself
re-loading the grains and re-packing these new grains into the
__grains__ dunder, negating the refresh.

Since the module refresh loads the grains anyway, this commit changes
saltutil.refresh_grains to refresh the modules. It also removes the
refresh argument recently added to the grains module functions, as we're
no longer using it to conditionally refresh modules.

salt/modules/grains.py

@@ -203,7 +203,7 @@ def item(*args, **kwargs):
     return ret
 
 
-def setvals(grains, destructive=False, refresh=True):
+def setvals(grains, destructive=False):
     '''
     Set new grains values in the grains config file
 
@@ -211,10 +211,6 @@ def setvals(grains, destructive=False, refresh=True):
         If an operation results in a key being removed, delete the key, too.
         Defaults to False.
 
-    refresh
-        Refresh modules and pillar after adding the new grains.
-        Defaults to True.
-
     CLI Example:
 
     .. code-block:: bash
@@ -290,12 +286,12 @@ def setvals(grains, destructive=False, refresh=True):
         log.error(msg.format(fn_))
     if not __opts__.get('local', False):
         # Refresh the grains
-        __salt__['saltutil.refresh_grains'](refresh=refresh)
+        __salt__['saltutil.refresh_grains']()
     # Return the grains we just set to confirm everything was OK
     return new_grains
 
 
-def setval(key, val, destructive=False, refresh=True):
+def setval(key, val, destructive=False):
     '''
     Set a grains value in the grains config file
 
@@ -309,10 +305,6 @@ def setval(key, val, destructive=False, refresh=True):
         If an operation results in a key being removed, delete the key, too.
         Defaults to False.
 
-    refresh
-        Refresh modules and pillar after adding the new grain.
-        Defaults to True.
-
     CLI Example:
 
     .. code-block:: bash
@@ -320,7 +312,7 @@ def setval(key, val, destructive=False, refresh=True):
         salt '*' grains.setval key val
         salt '*' grains.setval key "{'sub-key': 'val', 'sub-key2': 'val2'}"
     '''
-    return setvals({key: val}, destructive, refresh)
+    return setvals({key: val}, destructive)
 
 
 def append(key, val, convert=False, delimiter=DEFAULT_TARGET_DELIM):

salt/modules/saltutil.py

@@ -310,16 +310,19 @@ def sync_states(saltenv=None, refresh=True):
     return ret
 
 
-def refresh_grains(refresh=True):
+def refresh_grains(refresh_pillar=True):
     '''
     .. versionadded:: 2016.3.6,2016.11.4,Nitrogen
 
     Refresh the minion's grains without syncing custom grains modules from
     ``salt://_grains``.
 
-    refresh : True
-        If ``True``, refresh the available execution modules and recompile
-        pillar data for the minion. Set to ``False`` to prevent this refresh.
+    .. note::
+        The available execution modules will be reloaded as part of this
+        proceess, as grains can affect which modules are available.
+
+    refresh_pillar : True
+        Set to ``False`` to keep pillar data from being refreshed.
 
     CLI Examples:
 
@@ -327,13 +330,11 @@ def refresh_grains(refresh=True):
 
         salt '*' saltutil.refresh_grains
     '''
-    try:
-        ret = __salt__['event.fire']({}, 'grains_refresh_manual')
-    except Exception:
-        log.error('Failed to refresh grains', exc_info=True)
-        return False
-    if refresh:
-        refresh_modules()
+    # Modules and pillar need to be refreshed in case grains changes affected
+    # them, and the module refresh process reloads the grains and assigns the
+    # newly-reloaded grains to each execution module's __grains__ dunder.
+    refresh_modules()
+    if refresh_pillar:
         refresh_pillar()
     return ret