relevant_changes: rename a constant

We refer to this feature all over the place as "history aware submit",
but the most important constant about it doesn't include the word
"history", making it hard to find.

BUG=None
TEST=grep for old name, no results

Change-Id: I4dd995b1c6800f3485a71cbe61edb66d05483306
Reviewed-on: https://chromium-review.googlesource.com/726306
Commit-Ready: Aviv Keshet <akeshet@chromium.org>
Tested-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Ningning Xia <nxia@chromium.org>
1 file changed