Merge branch 'ab/grep-lose-opt-regflags'

Code cleanup.

* ab/grep-lose-opt-regflags:
grep: remove redundant REG_NEWLINE when compiling fixed regex
grep: remove regflags from the public grep_opt API
grep: remove redundant and verbose re-assignments to 0
grep: remove redundant "fixed" field re-assignment to 0
grep: adjust a redundant grep pattern type assignment
grep: remove redundant double assignment to 0

diff --cc builtin/grep.c
Simple merge

diff --cc revision.c
Simple merge