When renaming the lock file succeeds the lock isn't held anymore

This wrong book-keeping caused IOExceptions to be thrown because
LockFile.unlock() erroneously tried to delete the non-existing lock
file. These IOExeptions were hidden since they were silently caught. 

Change-Id: If42b6192d92c5a2d8f2bf904b16567ef08c32e89
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/LockFile.java

@@ -437,11 +437,16 @@ public class LockFile {
 		}
 
 		saveStatInformation();
-		if (lck.renameTo(ref))
+		if (lck.renameTo(ref)) {
+			haveLck = false;
 			return true;
-		if (!ref.exists() || deleteRef())
+		}
-			if (renameLock())
+		if (!ref.exists() || deleteRef()) {
+			if (renameLock()) {
+				haveLck = false;
 				return true;
+			}
+		}
 		unlock();
 		return false;
 	}