.gitignore: Add vim swap files

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
[ ijc -- corrected .hgignore regex syntax ]

.gitignore

@@ -2,6 +2,7 @@
 *.orig
 *.rej
 *~
+*.swp
 *.o
 *.d
 *.opic

.hgignore

@@ -11,6 +11,7 @@
 .*\.tar\.bz2$
 .*\.tar\.gz$
 .*~$
+.*\.swp$
 .*\.tmp$
 .*\.flc$
 .*\.orig$