Make udiff print reasonable errors while not on a branch.

Make udiff print reasonable errors while not on a branch.

R=agable@chromium.org
BUG=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=259647

[agable, 2014-03-26 15:36:24]

LGTM

https://codereview.chromium.org/212493002/diff/1/git_upstream_diff.py
File git_upstream_diff.py (right):

https://codereview.chromium.org/212493002/diff/1/git_upstream_diff.py#newcode11
git_upstream_diff.py:11: from git_common import current_branch,
get_or_create_merge_base, config_list
Would be good to sort these imports.

https://codereview.chromium.org/212493002/diff/1/git_upstream_diff.py#newcode32
git_upstream_diff.py:32: print 'fatal: branch %s has no configured upstream' %
cur
fatal: branch.%s.merge is not configured
?

[iannucci, 2014-03-26 18:51:10]

https://chromiumcodereview.appspot.com/212493002/diff/1/git_upstream_diff.py
File git_upstream_diff.py (right):

https://chromiumcodereview.appspot.com/212493002/diff/1/git_upstream_diff.py#...
git_upstream_diff.py:11: from git_common import current_branch,
get_or_create_merge_base, config_list
On 2014/03/26 15:36:24, agable wrote:
> Would be good to sort these imports.

Done.

https://chromiumcodereview.appspot.com/212493002/diff/1/git_upstream_diff.py#...
git_upstream_diff.py:32: print 'fatal: branch %s has no configured upstream' %
cur
On 2014/03/26 15:36:24, agable wrote:
> fatal: branch.%s.merge is not configured
> ?

Yeah, but it's also ...remote. I'm changing to the standard git error message.

[iannucci, 2014-03-26 18:51:19]

The CQ bit was checked by iannucci@chromium.org

[commit-bot: I haz the power, 2014-03-26 18:53:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/iannucci@chromium.org/212493002/50001

[commit-bot: I haz the power, 2014-03-26 18:55:41]

Change committed as 259647