Currently, calling a command like "git cl patch crrev.com/c/1234567"
will fail with "git cl: error: Invalid issue ID or URL." as no scheme is
supplied (i.e. "git cl patch https://crrev.com/c/1234567" is considered
valid).

This cl removes the requirement for supplying a scheme. Instead, the
script attempts to add "https://" where it would've thrown an error
previously. If the resulting string is valid, it is used. Otherwise, an
error will still be thrown.

Bug: 1223200
Change-Id: I24ee4df48b5f5d434f3abe270f5c3e793c347cc8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2983443Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Alex Turner <alexmt@chromium.org>