Vcs: Dissolve VcsManager::registerVersionControl

It's a somewhat unusual pattern, spelling it out will help
to move the vcs plugins setup closer to the now-usual pattern.

Change-Id: Ie7b70e52d75e34cd36b6a1d55ca868e3edab44a7
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/git/gitplugin.cpp

@@ -299,7 +299,8 @@ bool GitPlugin::initialize(const QStringList &arguments, QString *errorMessage)
 
     m_gitClient = new GitClient;
 
-    auto vc = initializeVcs<GitVersionControl>(context, m_gitClient);
+    auto vc = new GitVersionControl(m_gitClient);
+    initializeVcs(vc, context);
 
     // Create the settings Page
     auto settingsPage = new SettingsPage(vc, this);