Updates .gitignore

To ignore swap files from getting into repository
currently the implemented ignore is *.swp
however vim adds more swap files if these files exists,
so improving this with *.sw?

Change-Id: Ic4a1a85dfdf21b7bd0abdf16a205446febab2fcd
Closes-Bug: #1255887

.gitignore

@@ -1,6 +1,6 @@
 *~
 .testrepository
-*.swp
+*.sw?
 *.pyc
 .tox
 *.egg