Change 'RUN=' to 'RUN+=' to let other block rules run.

Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>

diff --git a/utils/99-petitboot.rules b/utils/99-petitboot.rules
index 876bdf3..ab3c984 100644
--- a/utils/99-petitboot.rules
+++ b/utils/99-petitboot.rules
@@ -1,2 +1,2 @@
 # tell petitboot when we see new block devices ...
-SUBSYSTEM=="block",RUN="socket:/tmp/petitboot.udev"
+SUBSYSTEM=="block", RUN+="socket:/tmp/petitboot.udev"

--