Fix update checking, was not done only once per day

mpcdf_common.py

@@ -90,6 +90,7 @@ def check_for_update():
     with open(rev_file, "r") as fd:
         server_rev = fd.read().strip()
 
+    if server_rev != local_rev:
         if call(["git", "--git-dir", git_dir, "merge-base", "--is-ancestor", server_rev, "HEAD"], stderr=DEVNULL) == 0:
             # Server rev is older than ours. Check again
             update_server_rev()