.gitignore: add temporary *~ files

Ignore any ~ files left in the repository.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
diff --git a/.gitignore b/.gitignore
index 5569f98..7565fd5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,6 +5,7 @@
 *.so
 .*.swp
 *.pyc
+*~
 
 # generated
 version.h