Updated .gitmodules for easier access to ownCloud library from different environments

.gitmodules

@@ -3,4 +3,4 @@
 	url = git://github.com/JakeWharton/ActionBarSherlock.git
 [submodule "owncloud-android-library"]
 	path = owncloud-android-library
-	url = git@github.com:owncloud/android-library.git
+	url = git://github.com/owncloud/android-library.git