Merge branch 'jt/fetch-v2-sideband'

"git fetch" and "git upload-pack" learned to send all exchange over
the sideband channel while talking the v2 protocol.

* jt/fetch-v2-sideband:
t/lib-httpd: pass GIT_TEST_SIDEBAND_ALL through Apache

diff --cc t/lib-httpd.sh
Simple merge