gerrit: drop --external and add --gob
gerrit: drop --external and add --gob

Since the default is --external, having a dedicated option isn't terribly
useful.  Instead, let's add a --gob option so people can pick an arbitrary
host to query (although it only works for Chrome remotes atm).

BUG=chromium:327217
TEST=queried some internal & external CLs via `gerrit inspect`

Change-Id: Ic8754c0ec05f7cdcf2838a2b7e9b42a9cfcd46d5
Reviewed-on: https://chromium-review.googlesource.com/185692
Reviewed-by: Gaurav Shah <2987db6a10bcfe664554a372d01e80df7fd325a3@chromium.org>
Tested-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>

chadversary/chromiumos.chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite