[gnome-continuous] vcs: don't crash if submodule checkout failed

[Vadim Rutkovsky <vrutkovsky src gnome org>]

commit 232923dd426ba8eb05a9ea73f15d3d6662320e2b
Author: Vadim Rutkovsky <vrutkovs redhat com>
Date:   Wed Apr 16 21:21:33 2014 +0200

    vcs: don't crash if submodule checkout failed
    
    https://bugzilla.gnome.org/show_bug.cgi?id=728366

 src/js/vcs.js |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/src/js/vcs.js b/src/js/vcs.js
index 67fc010..bdb8e9e 100644
--- a/src/js/vcs.js
+++ b/src/js/vcs.js
@@ -166,8 +166,12 @@ function _listSubmodules(mirrordir, mirror, keytype, uri, branch, cancellable) {
     GSystem.shutil_rm_rf(tmpCheckout, cancellable);
     GSystem.file_ensure_directory(tmpCheckout.get_parent(), true, cancellable);
     ProcUtil.runSync(['git', 'clone', '-q', '--no-checkout', mirror.get_path(), tmpCheckout.get_path()], 
cancellable);
-    ProcUtil.runSync(['git', 'checkout', '-q', '-f', currentVcsVersion], cancellable,
-                    {cwd: tmpCheckout});
+    try{
+        ProcUtil.runSync(['git', 'checkout', '-q', '-f', currentVcsVersion], cancellable, {cwd: 
tmpCheckout});
+    } catch (e) {
+        print("Failed to checkout revision "+currentVcsVersion);
+        return [];
+    }
     let submodules = []
     let lines = ProcUtil.runSyncGetOutputLines(['git', 'submodule', 'status'],
                                               cancellable, {cwd: tmpCheckout});