Getting prepared for relative submodule specs

.gitmodules file may have relative submodule paths instead of full
url.

Change-Id: Ib4f00cb2a75a00ffdb7465b669354e0bf7bab1f9
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>
Reviewed-by: Janne Anttila <janne.anttila@digia.com>

scripts/qt/qt_update_submodules.pl

@@ -266,6 +266,12 @@ sub update_submodule
         confess "Command `@cmd' did not output a giturl";
     }
 
+    # Let's be prepared for relative paths in .gitmodules
+    if ($giturl eq "../$submodule.git") {
+        $giturl = trim $self->exe( qw(git config --file), ".git/config", "remote.origin.url" );
+        $giturl =~ s,[^/]+$,$submodule.git,;
+    }
+
     chdir catfile($base_dir, $submodule);
     $self->exe( qw(git fetch --verbose), $giturl, "+$ref:refs/heads/updated_submodule" );