10328 git pbchk falls over with no changesets

@@ -123,11 +123,11 @@
     p = git(["for-each-ref", "--format=%(refname:short) %(upstream:short)",
             "refs/heads/"])
 
     if not p:
         sys.stderr.write("Failed finding git parent branch\n")
-        sys.exit(err)
+        sys.exit(1)
 
     for line in p:
         # Git 1.7 will leave a ' ' trailing any non-tracking branch
         if ' ' in line and not line.endswith(' \n'):
             local, remote = line.split()

@@ -139,12 +139,12 @@
     """Return a list of any checkin comments on this git branch"""
 
     p = git('log --pretty=tformat:%%B:SEP: %s..' % parent)
 
     if not p:
-        sys.stderr.write("Failed getting git comments\n")
-        sys.exit(err)
+        sys.stderr.write("No outgoing changesets found - missing -p option?\n");
+        sys.exit(1)
 
     return [x.strip() for x in p if x != ':SEP:\n']
 
 def git_file_list(parent, paths=None):
     """Return the set of files which have ever changed on this branch.

@@ -155,11 +155,11 @@
     p = git("log --name-only --pretty=format: %s.. %s" %
              (parent, ' '.join(paths)))
 
     if not p:
         sys.stderr.write("Failed building file-list from git\n")
-        sys.exit(err)
+        sys.exit(1)
 
     ret = set()
     for fname in p:
         if fname and not fname.isspace() and fname not in ret:
             ret.add(fname.strip())