Adapt expected commit message in tests

Because of change I28ae5713, the commit message lost the "into HEAD" and
caused the MergeCommandTest to fail. This change fixes it.

Bug: 336059
Change-Id: Ifac0138c6c6d66c40d7295b5e11ff3cd98bc9e0c

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

@@ -364,7 +364,7 @@ public class MergeCommandTest extends RepositoryTestCase {
 		assertEquals(thirdCommit, newHead.getParent(0));
 		assertEquals(secondCommit, newHead.getParent(1));
 		assertEquals(
-				"Merge commit '3fa334456d236a92db020289fe0bf481d91777b4' into HEAD",
+				"Merge commit '3fa334456d236a92db020289fe0bf481d91777b4'",
 				newHead.getFullMessage());
 		// @TODO fix me
 		assertEquals(RepositoryState.SAFE, db.getRepositoryState());
@@ -425,7 +425,7 @@ public class MergeCommandTest extends RepositoryTestCase {
 		assertEquals(thirdCommit, newHead.getParent(0));
 		assertEquals(secondCommit, newHead.getParent(1));
 		assertEquals(
-				"Merge commit '064d54d98a4cdb0fed1802a21c656bfda67fe879' into HEAD",
+				"Merge commit '064d54d98a4cdb0fed1802a21c656bfda67fe879'",
 				newHead.getFullMessage());
 
 		assertEquals(RepositoryState.SAFE, db.getRepositoryState());