add .protoset to extensions ignored for licensecheck

Change-Id: I86e47c4711b39529e491800b3c4a599034e0d93b
diff --git a/jjb/shell/licensecheck.sh b/jjb/shell/licensecheck.sh
index 0eb26ea..217e3b5 100755
--- a/jjb/shell/licensecheck.sh
+++ b/jjb/shell/licensecheck.sh
@@ -73,6 +73,7 @@
   ! -name "*.png" \
   ! -name "*.properties" \
   ! -name "*.proto" \
+  ! -name "*.protoset" \
   ! -name "*.pyc" \
   ! -name "*.repo" \
   ! -name "*.robot" \