revert: Don't create invalid replay_opts in parse_args
revert: Don't create invalid replay_opts in parse_args

The "--ff" command-line option cannot be used with some other
command-line options.  However, parse_args still parses these
incompatible options into a replay_opts structure for use by the rest
of the program.  Although pick_commits, the current gatekeeper to the
cherry-pick machinery, checks the validity of the replay_opts
structure before before starting its operation, there will be multiple
entry points to the cherry-pick machinery in future.  To futureproof
the code and catch these errors in one place, make sure that an
invalid replay_opts structure is not created by parse_args in the
first place.  We still check the replay_opts structure for validity in
pick_commits, but this is an assert() now to emphasize that it's the
caller's responsibility to get it right.

Inspired-by: Christian Couder <ddbaab5867ed34fd53535b58c9cdd59abd2e2aff@tuxfamily.org>
Mentored-by: Jonathan Nieder <b57189c5f2fd5b3daf3350a77fde90def1080fa5@gmail.com>
Helped-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>
Signed-off-by: Ramkumar Ramachandra <5c355d1d38066ed0c5de420d67c1b5ed0687c4bd@gmail.com>
Signed-off-by: Jonathan Nieder <b57189c5f2fd5b3daf3350a77fde90def1080fa5@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git