[libgee] Fix compilation error, fixes bug #690723

[Maciej Marcin Piechotka <mpiechotka src gnome org>]

commit 9af15d5b5930a57acf3e8dd9a8c2b2d9bfef3221
Author: Maciej Piechotka <uzytkownik2 gmail com>
Date:   Wed Dec 26 10:26:09 2012 +0100

    Fix compilation error, fixes bug #690723

 gee/concurrentset.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gee/concurrentset.vala b/gee/concurrentset.vala
index 854340f..c0d3d75 100644
--- a/gee/concurrentset.vala
+++ b/gee/concurrentset.vala
@@ -1078,7 +1078,7 @@ public class Gee.ConcurrentSet<G> : AbstractSortedSet<G> {
 		}
 
 		inline ~Tower () {
-			uint8 height = get_height();
+			int height = get_height();
 			for (uint8 i = 0; i < height; i++) {
 				set_succ (null, State.NONE, i);
 				set_backlink (null, i);