[meld] fix typeerror when folder compare

[Kai Willadsen <kaiw src gnome org>]

commit e4aa5761f4b536d13749f2ac5aaf2700979f9353
Author: Alsan Wong <awxhuang fsll cn>
Date:   Wed Jul 12 14:46:34 2017 +0800

    fix typeerror when folder compare

 meld/dirdiff.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meld/dirdiff.py b/meld/dirdiff.py
index a4e331f..cd8314e 100644
--- a/meld/dirdiff.py
+++ b/meld/dirdiff.py
@@ -94,7 +94,7 @@ def remove_blank_lines(text):
     lines = text.splitlines(True)
     blanks = set([i for i, l in enumerate(splits) if not l])
     lines = [l for i, l in enumerate(lines) if i not in blanks]
-    return ''.join(lines)
+    return b''.join(lines)
 
 
 def _files_same(files, regexes, comparison_args):