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
%% no merges expected
%% merge should fail
abort: 'b' already exists in the working dir and differs from remote
%% merge of b expected
merging for b
merging b
%%
Contents of b should be "this is file b1"
This is file b1
%% merge fails
abort: outstanding uncommitted changes
%% merge expected!
merging for b
merging b
%% merge of b should fail
abort: outstanding uncommitted changes
%% merge of b expected
merging for b
merging b