Merge branch 'ds/rev-parse-required-args' into maint

"git rev-parse" was loose in rejecting command line arguments that
do not make sense, e.g. "--default" without the required value for
that option.

* ds/rev-parse-required-args:
  rev-parse: check i before using argv[i] against argc

diff --cc builtin/rev-parse.c
Simple merge