Ensure non-async deactivate is run syncronously without await

src/package.coffee

@@ -506,18 +506,30 @@ class Package
     @configSchemaRegisteredOnActivate = false
     @deactivateResources()
     @deactivateKeymaps()
-    result = Promise.resolve()
-    if @mainActivated
-      try
-        result = Promise.resolve(@mainModule?.deactivate?()).then =>
-          @mainModule?.deactivateConfig?()
-          @mainActivated = false
-          @mainInitialized = false
-      catch e
-        console.error "Error deactivating package '#{@name}'", e.stack
-    result = result.then =>
+
+    unless @mainActivated
       @emitter.emit 'did-deactivate'
-    result
+      return
+
+    try
+      deactivationResult = @mainModule?.deactivate?()
+    catch e
+      console.error "Error deactivating package '#{@name}'", e.stack
+
+    # We support then-able async promises as well as sync ones from deactivate
+    if deactivationResult?.then is 'function'
+      deactivationResult.then => @afterDeactivation()
+    else
+      @afterDeactivation()
+
+  afterDeactivation: ->
+    try
+      @mainModule?.deactivateConfig?()
+    catch e
+      console.error "Error deactivating package '#{@name}'", e.stack
+    @mainActivated = false
+    @mainInitialized = false
+    @emitter.emit 'did-deactivate'
 
   deactivateResources: ->
     grammar.deactivate() for grammar in @grammars