unpack-trees: use 'cuddled' style for if-else cascade

Match the predominant style in git by following K&R style for if/else
cascades.  Documentation/CodingStyle from linux.git explains:

  Note that the closing brace is empty on a line of its own, _except_ in
  the cases where it is followed by a continuation of the same statement,
  ie a "while" in a do-statement or an "else" in an if-statement, like
  this:

	if (x == y) {
		..
	} else if (x > y) {
		...
	} else {
		....
	}

  Rationale: K&R.

  Also, note that this brace-placement also minimizes the number of empty
  (or almost empty) lines, without any loss of readability.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

unpack-trees.c

@@ -1771,8 +1771,7 @@ int twoway_merge(const struct cache_entry * const *src,
 					return merged_entry(newtree, current, o);
 			}
 			return o->gently ? -1 : reject_merge(current, o);
-		}
-		else if ((!oldtree && !newtree) || /* 4 and 5 */
+		} else if ((!oldtree && !newtree) || /* 4 and 5 */
 			 (!oldtree && newtree &&
 			  same(current, newtree)) || /* 6 and 7 */
 			 (oldtree && newtree &&
@@ -1781,17 +1780,14 @@ int twoway_merge(const struct cache_entry * const *src,
 			  !same(oldtree, newtree) && /* 18 and 19 */
 			  same(current, newtree))) {
 			return keep_entry(current, o);
-		}
-		else if (oldtree && !newtree && same(current, oldtree)) {
+		} else if (oldtree && !newtree && same(current, oldtree)) {
 			/* 10 or 11 */
 			return deleted_entry(oldtree, current, o);
-		}
-		else if (oldtree && newtree &&
+		} else if (oldtree && newtree &&
 			 same(current, oldtree) && !same(current, newtree)) {
 			/* 20 or 21 */
 			return merged_entry(newtree, current, o);
-		}
-		else
+		} else
 			return o->gently ? -1 : reject_merge(current, o);
 	}
 	else if (newtree) {