initfs: whitelist: Sanitize obmc events whitelist entry

Remove the trailing / so that the update script doesn't have to loop.

It was determined the trailing slash confused the code that makes
the save subdirectory.  The update script was fixed but this removes
the extra work needed.

Signed-off-by: Milton Miller <miltonm@us.ibm.com>
diff --git a/common/recipes-phosphor/obmc-phosphor-initfs/files/whitelist b/common/recipes-phosphor/obmc-phosphor-initfs/files/whitelist
index 603cec7..c35a552 100644
--- a/common/recipes-phosphor/obmc-phosphor-initfs/files/whitelist
+++ b/common/recipes-phosphor/obmc-phosphor-initfs/files/whitelist
@@ -6,4 +6,4 @@
 /etc/group
 /etc/shadow
 /etc/gshadow
-/var/lib/obmc/events/
+/var/lib/obmc/events