Try resolving key paths from cwd

See mitchellh#159 and d821468

lib/vagrant-google/action/connect_google.rb

@@ -36,9 +36,9 @@ def call(env)
             :google_client_email => provider_config.google_client_email
           }
           if provider_config.google_json_key_location.nil?
-            fog_config[:google_key_location] = provider_config.google_key_location
+            fog_config[:google_key_location] = find_key(provider_config.google_key_location, env)
           else
-            fog_config[:google_json_key_location] = provider_config.google_json_key_location
+            fog_config[:google_json_key_location] = find_key(provider_config.google_json_key_location, env)
           end
 
           @logger.info("Connecting to Google...")
@@ -47,6 +47,15 @@ def call(env)
           @app.call(env)
           @logger.info("...Connected!")
         end
+
+        # If the key is not found, try expanding from root location (see #159)
+        def find_key(location, env)
+           if File.file?(location)
+             return location
+           else
+             return File.expand_path(location, env[:root_path])
+           end
+        end
       end
     end
   end