simplify variable names

contrib/inventory/ec2.py

@@ -514,11 +514,11 @@ class Ec2Inventory(object):
 
         return '\n'.join(errors)
 
-    def fail_with_error(self, err_msg, err_operation_context=None):
+    def fail_with_error(self, err_msg, err_operation=None):
         '''log an error to std err for ansible-playbook to consume and exit'''
-        if err_operation_context:
+        if err_operation:
             err_msg = 'ERROR: "{err_msg}", while: {err_operation}'.format(
-                err_msg=err_msg, err_operation=err_operation_context)
+                err_msg=err_msg, err_operation=err_operation)
         sys.stderr.write(err_msg)
         sys.exit(1)