[google|compute] reraise LoadError when google-api-client missing

lib/fog/google/compute.rb

@@ -854,8 +854,9 @@ module Fog
           # NOTE: loaded here to avoid requiring this as a core Fog dependency
           begin
             require 'google/api_client'
-          rescue LoadError
+          rescue LoadError => error
             Fog::Logger.warning("Please install the google-api-client gem before using this provider.")
+            raise error
           end
           key = ::Google::APIClient::KeyUtils.load_from_pkcs12(File.expand_path(options[:google_key_location]), 'notasecret')