.gitignore: Ignore distcheck directories

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Luca Bigliardi <shammash@google.com>

.gitignore

@@ -26,6 +26,7 @@
 /*.patch
 /*.tar.bz2
 /*.tar.gz
+/ganeti-[0-9]*.[0-9]*.[0-9]*
 
 # daemons
 /daemons/ganeti-cleaner