check-whitespace.sh: enable the TAB checking again
check-whitespace.sh: enable the TAB checking again

https://bugzilla.gnome.org/show_bug.cgi?id=699492

GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets,Distrotech/telepathy-account-widgets,GNOME/telepathy-account-widgets,GNOME/telepathy-account-widgets