git-submodule.sh: accept verbose flag in cmd_update to be non-quiet

In a56771a668d (builtin/pull: respect verbosity settings in submodules, 2018-01-25), we made sure to pass on both quiet and verbose flag from builtin/pull.c to the submodule shell script. However git-submodule doesn't understand a verbose flag, which results in a bug when invoking git pull --recurse-submodules -v [...] There are a few different approaches to fix this bug: 1) rewrite 'argv_push_verbosity' or its caller in builtin/pull.c to cap opt_verbosity at 0. Then 'argv_push_verbosity' would only add '-q' if any. 2) Have a flag in 'argv_push_verbosity' that specifies if we allow adding -q or -v (or both). 3) Add -v to git-submodule.sh and make it a no-op (1) seems like a maintenance burden: What if we add code after the submodule operations or move submodule operations higher up, then we have altered the opt_verbosity setting further down the line in builtin/pull.c. (2) seems like it could work reasonably well without more regressions (3) seems easiest to implement as well as actually is a feature with the last-one-wins rule of passing flags to Git commands. Reported-by: Jochen Kühner Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>