all: sync rc fix with master

bamboo-specs/release.yaml

@@ -40,6 +40,8 @@
         'jobs':
           - 'Publish to GitHub Releases'
 
+# TODO(e.burkov):  In jobs below find out why the explicit checkout is
+# performed.
 'Build frontend':
     'docker':
         'image': '${bamboo.dockerGo}'

bamboo-specs/test.yaml

@@ -68,9 +68,6 @@
 
                 set -e -f -u -x
 
-                # Explicitly checkout the revision that we need.
-                git checkout "${bamboo.repository.revision.number}"
-
                 make\
                         ARCH="amd64"\
                         OS="windows darwin linux"\