Use the first status

Previously it would use any commit status but the same context status
can now appear multiple times and the first entry is the most current
status, so we should only compare against that.

src/main/java/io/pivotal/cla/service/github/MylynGitHubApi.java

@@ -184,7 +184,8 @@ private ContextCommitStatus createCommitStatusIfNecessary(PullRequestId pullRequ
 		status.setUrl(commitStatus.getUrl());
 		status.setTargetUrl(status.getUrl());
 		List<ContextCommitStatus> statuses = commitService.getContextStatuses(pullRequestId.getRepositoryId(), commitStatus.getSha());
-		if (!statuses.stream().anyMatch(s -> matches(status, s))) {
+		ContextCommitStatus firstContextStatus = statuses.stream().filter(s -> s.getContext().equals(status.getContext())).findFirst().orElse(null);
+		if (firstContextStatus == null || !matches(status, firstContextStatus)) {
 			commitService.createStatus(pullRequestId.getRepositoryId(), commitStatus.getSha(), status);
 		}
 		return status;