revert: rename --reset option to --quit

revert: rename --reset option to --quit

The option to "git cherry-pick" and "git revert" to discard the
sequencer state introduced by v1.7.8-rc0~141^2~6 (revert: Introduce
--reset to remove sequencer state, 2011-08-04) has a confusing name.
Change it now, while we still have the time.

The new name for "cherry-pick, please get out of my way, since I've
long forgotten about the sequence of commits I was cherry-picking when
you wrote that old .git/sequencer directory" is --quit.  Mnemonic:
this is analagous to quiting a program the user is no longer using ---
we just want to get out of the multiple-command cherry-pick procedure
and not to reset HEAD or rewind any other old state.

The "--reset" option is kept as a synonym to minimize the impact.  We
might consider dropping it for simplicity in a separate patch, though.

Adjust documentation and tests to use the newly preferred name (--quit)
instead of --reset.  While at it, let's clarify the short descriptions
of these operations in "-h" output.

Before:

	--reset		forget the current operation
	--continue	continue the current operation

After:

	--quit		end revert or cherry-pick sequence
	--continue	resume revert or cherry-pick sequence

Noticed-by: Phil Hord <phil.hord@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>