linux-4.9.68: Check for existing revision number

We want our kernel revision numbers to be unique over all linux
kernel packages. Avoid conflicts by doing a quick check against
the available bee files.

Patch by Thomas Kreitler

linux-4.9.68-193.bee

@@ -25,6 +25,9 @@ FULLKERNELVERSION="${KERNELVERSION}${KERNELLOCAL}"
 
 B=${S}
 
+ls ${BEE_PKGDIR}/linux-[0-9].[0-9]*-${PKGREVISION}.x86_64.bee.* 2>/dev/null \
+    && echo "A kernel with revision ${PKGREVISION} has already been build."  && exit
+
 mee_patch() {
     echo "PATCH $@"
     bee_patch $@