Silence 'git unavailable' message

gajim/__init__.py

@@ -3,10 +3,10 @@ import subprocess
 __version__ = "0.99.2"
 
 try:
-    node = subprocess.Popen('git rev-parse --short=12 HEAD', shell=True,
-        stdout=subprocess.PIPE).communicate()[0]
+    p = subprocess.Popen('git rev-parse --short=12 HEAD', shell=True,
+                          stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)
+    node = p.communicate()[0]
     if node:
         __version__ += '+' + node.decode('utf-8').strip()
 except Exception:
     pass
-