common: mask out /usr/share/applications

This path only holds .desktop files which we never use anywhere in
CrOS, so scrub the path to avoid constantly regenerating caches.

BUG=None
TEST=CQ passes

Change-Id: I34a4bfc5fc3577c880d7547ef5cc837b322ed186
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3628561
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Sergey Frolov <sfrolov@google.com>
diff --git a/common.sh b/common.sh
index 43611ec..5ef02fc 100644
--- a/common.sh
+++ b/common.sh
@@ -427,6 +427,7 @@
   /usr/local/autotest-chrome
   /usr/man
   /usr/share/aclocal
+  /usr/share/applications
   /usr/share/cups/drv
   /usr/share/doc
   /usr/share/gettext