chg: always wait for pager...
chg: always wait for pager
Previously, when runcommand raises, chg aborts with, and does not wait for
pager. The call stack is like:
hgc_runcommand -> handleresponse -> readchannel -> debugmsg("failed to
read channel") -> exit(255)
That means, chg returns to the shell, then both the pager and the shell will
read from the terminal at the same time, causing problems.
This patch fixes that by using "atexit" to register the pager cleanup
function so chg will always wait for pager even if runcommand raises.
