sepgrep -- function to grep SELinux policy files.

(cherry picked from commit ba5fc8e59397ff2d986681457ed590742ce522e8)

Change-Id: I7840dc698c5e479e65c66cb2a3ab0405127b64ec
diff --git a/envsetup.sh b/envsetup.sh
index ae2ff93..2de2375 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -945,6 +945,11 @@
     find . -name .repo -prune -o -name .git -prune -o -path ./out -prune -o -type f -name 'AndroidManifest.xml' -print0 | xargs -0 grep --color -n "$@"
 }
 
+function sepgrep()
+{
+    find . -name .repo -prune -o -name .git -prune -o -path ./out -prune -o -name sepolicy -type d -print0 | xargs -0 grep --color -n -r --exclude-dir=\.git "$@"
+}
+
 case `uname -s` in
     Darwin)
         function mgrep()