Switch submodules to use git:// repo urls.

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "vendor/spec"]
 	path = vendor/spec
-	url = https://github.com/mustache/spec.git
+	url = git://github.com/mustache/spec.git
 [submodule "vendor/yaml"]
 	path = vendor/yaml
-	url = https://github.com/fabpot/yaml.git
+	url = git://github.com/fabpot/yaml.git