Add extra vim swap file pattern



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@165570 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/.gitignore b/.gitignore
index b906ab9..6be9976 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,7 @@
 *.pyc
 # vim swap files
 .*.swp
+.sw?
 
 #==============================================================================#
 # Explicit files to ignore (only matches one).