Ignore EPIPE in pipefilter
This hides the following traceback (there's a race condition involved,
so you may have to try a few times to hit it):
$ hg sign --key key-that-does-not-exist
Signing 2062:4bad92f4ea65
gpg: skipped "key-that-does-not-exist": secret key not available
gpg: signing failed: secret key not available
Exception in thread Thread-1:
Traceback (most recent call last):
File "threading.py", line 442, in __bootstrap
self.run()
File "threading.py", line 422, in run
self.__target(*self.__args, **self.__kwargs)
File "mercurial/util.py", line 24, in writer
pin.close()
IOError: [Errno 32] Broken pipe
abort: Error while signing
adding foo
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
pulling from ../branch
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 2 changesets, 2 total revisions
foo
bar
6f4310b00b9a147241b071a60c28a650827fb03d 644 foo