keyword: remove "help keyword" from test
Testing help output does not make sense as we have no way to
check for errors in content which would be the only reasonable
test here.
adding foo
% no signatures
% hg sign 0
Signing 0:e63c23eaa88a
% hg sigs
hgtest 0:e63c23eaa88ae77967edcf4ea194d31167c478b0
% hg sigcheck 0
e63c23eaa88a is signed by:
hgtest