Set git sha from parameter

Because we merge master into the branch before running tests, so the
actual git sha does not exist on any git remote.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

hack/ci/janky

@@ -4,7 +4,9 @@ set -eu -o pipefail
 
 hack/validate/default
 hack/test/unit
-bash <(curl -s https://codecov.io/bash) -f coverage.txt || \
+bash <(curl -s https://codecov.io/bash) \
+    -f coverage.txt \
+    -C $GIT_SHA1 || \
     echo 'Codecov failed to upload'
 
 hack/make.sh \