Rspec: mock `hg_git` as allowed VCS type

--HG--
branch : heptapod
12 jobs for !272 with topic/heptapod/make-native-default in 15 minutes and 41 seconds (queued for 3 seconds)
latest detached
Status Name Job ID Coverage
  Lint
passed rubocop #246940

00:03:54

 
  Test
passed rspec-regular 1/8 #246944

00:08:11

passed rspec-regular 2/8 #246945

00:07:30

passed rspec-regular 3/8 #246946

00:07:01

passed rspec-regular 4/8 #246947

00:07:32

passed rspec-regular 5/8 #246948

00:07:53

passed rspec-regular 6/8 #246949

00:11:45

passed rspec-regular 7/8 #246950

00:08:00

passed rspec-regular 8/8 #246951

00:08:10

passed workhorse:test using go 1.15 #246942

00:01:35

passed workhorse:test using go 1.16 #246943

00:01:36

passed workhorse:verify #246941

00:01:31