[meld] Fix logic error in blank line consumption (closes bgo#691810)

[Kai Willadsen <kaiw src gnome org>]

commit 67bd7460bc1ae72bee8b381dd555efe6964ad6b5
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Fri Jan 18 05:39:13 2013 +1000

    Fix logic error in blank line consumption (closes bgo#691810)

 meld/diffutil.py |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/meld/diffutil.py b/meld/diffutil.py
index c80bf93..fd9f707 100644
--- a/meld/diffutil.py
+++ b/meld/diffutil.py
@@ -42,9 +42,9 @@ def consume_blank_lines(chunk, texts, pane1, pane2):
         return None
 
     def _find_blank_lines(txt, lo, hi):
-        while not txt[lo] and lo < hi:
+        while lo < hi and not txt[lo]:
             lo += 1
-        while not txt[hi - 1] and lo < hi:
+        while lo < hi and not txt[hi - 1]:
             hi -= 1
         return lo, hi