pager: remove quiet flag
With the pager running as a child process, exiting the pager doesn't
result in a broken pipe message. To distinguish the exit broken pipe code
from a mercurial abort we register the default action for SIGPIPE. This
results in a 141 exit code instead of a 255. On windows SIGPIPE doesn't
exists and a ValueError will be thrown.
% creating repo
% add and commit
C test.py
% change
M test.py