Remove excess period

The error is supplemented by ", message: " + exception

As such, a period is unhelpful.

Fixes #9749

Author: jsoref

lib/pluginmanager/remove.rb

@@ -33,6 +33,6 @@ def execute
 
     remove_unused_locally_installed_gems!
   rescue => exception
-    report_exception("Operation aborted, cannot remove plugin.", exception)
+    report_exception("Operation aborted, cannot remove plugin", exception)
   end
 end