DeleteBranchCommand does not clean up upstream configuration

It wrongly uses the full name of the branch to remove the
configuration entries but must use the shortened one.

Change-Id: Ie386a128a6c6beccc20bafd15c2e36254c5f560d
Signed-off-by: Mathias Kinzler <mathias.kinzler@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/BranchCommandTest.java

 		// the pull configuration should be gone after deletion
 		assertNull(localGit.getRepository().getConfig().getString("branch",
 				"newFromRemote", "remote"));
+
+		createBranch(localGit, "newFromRemote", false, remote.getName(), null);
+		assertEquals("origin", localGit.getRepository().getConfig().getString(
+				"branch", "newFromRemote", "remote"));
+		localGit.branchDelete().setBranchNames("refs/heads/newFromRemote")
+				.call();
+		// the pull configuration should be gone after deletion
+		assertNull(localGit.getRepository().getConfig().getString("branch",
+				"newFromRemote", "remote"));
+
 		// use --no-track
 		createBranch(localGit, "newFromRemote", false, remote.getName(),
 				SetupUpstreamMode.NOTRACK);
 				SetupUpstreamMode.TRACK);
 		assertEquals(".", localGit.getRepository().getConfig().getString(
 				"branch", "newFromMaster", "remote"));
-		localGit.branchDelete().setBranchNames("newFromMaster").call();
+		localGit.branchDelete().setBranchNames("refs/heads/newFromMaster")
+				.call();
 		// the pull configuration should be gone after deletion
 		assertNull(localGit.getRepository().getConfig().getString("branch",
 				"newFromRemote", "remote"));

org.eclipse.jgit/src/org/eclipse/jgit/api/DeleteBranchCommand.java

 				Ref currentRef = repo.getRef(branchName);
 				if (currentRef == null)
 					continue;
-				if (currentRef.getName().equals(currentBranch))
+				String fullName = currentRef.getName();
+				if (fullName.equals(currentBranch))
 					throw new CannotDeleteCurrentBranchException(
 							MessageFormat
 									.format(
 											JGitText.get().cannotDeleteCheckedOutBranch,
 											branchName));
-				RefUpdate update = repo.updateRef(currentRef.getName());
+				RefUpdate update = repo.updateRef(fullName);
 				update.setRefLogMessage("branch deleted", false);
 				update.setForceUpdate(true);
 				Result deleteResult = update.delete();
 				}
 
 				if (ok) {
-					result.add(currentRef.getName());
-					// remove upstream configuration if any
-					repo.getConfig().unsetSection(
-							ConfigConstants.CONFIG_BRANCH_SECTION, branchName);
-					repo.getConfig().save();
+					result.add(fullName);
+					if (fullName.startsWith(Constants.R_HEADS)) {
+						String shortenedName = fullName
+								.substring(Constants.R_HEADS.length());
+						// remove upstream configuration if any
+						repo.getConfig().unsetSection(
+								ConfigConstants.CONFIG_BRANCH_SECTION,
+								shortenedName);
+						repo.getConfig().save();
+					}
 				} else
 					throw new JGitInternalException(MessageFormat.format(
 							JGitText.get().deleteBranchUnexpectedResult,