bitbake: hob/builddetailspage: change branch field

When a user makes a build from a tarball, it shows fatal error in branch field.
Now it not complains as a fatal error. It is a normal message.

[YOCTO #3114]

(Bitbake rev: 53d5d542cd0197ca67c5f90a57808af2f19ff56d)

Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/ui/crumbs/builddetailspage.py

@@ -99,6 +99,8 @@ class BuildConfigurationTreeView(gtk.TreeView):
             import os, os.path
             if os.path.exists(path):
                 branch = bb.process.run('cd %s; git branch | grep "^* " | tr -d "* "' % path)[0]
+                if branch.startswith("fatal:"):
+                    branch = "(unknown)"
                 if branch:
                     branch = branch.strip('\n')
                     vars.append(self.set_vars("Branch:", branch))