Abbreviate SHA-1 in output to client

Created by: spearce

getId().toString() returns an ugly internal JGit string listing the current revision flags attached to the RevCommit. This is not interesting or relevant to the end-user of Gerrit.

Instead abbreviate the SHA-1 to be 8 hex digits and print that as a clean string. For most Git repositories this will be uniquely identified. It is shorter to use in commands like git show when the end-user wants to inspect a commit that was rejected by the CLA plugin.

eclipse-cla/src/main/java/org/eclipse/foundation/gerrit/validation/EclipseCommitValidationListener.java

@@ -109,7 +109,7 @@ public class EclipseCommitValidationListener implements CommitValidationListener
 		
 		List<CommitValidationMessage> messages = new ArrayList<CommitValidationMessage>();
 		addSeparatorLine(messages);
-		messages.add(new CommitValidationMessage(String.format("Reviewing commit: %1$s", commit.getId()), false));
+		messages.add(new CommitValidationMessage(String.format("Reviewing commit: %1$s", commit.abbreviate(8).name()), false));
 		messages.add(new CommitValidationMessage(String.format("Authored by: %1$s <%2$s>", authorIdent.getName(), authorIdent.getEmailAddress()), false));
 		addEmptyLine(messages);