cli: show event -id accept strings instead of numeric values(#886786)

Show event -id does not accept numeric values.

This patch does and explicit cast into string for ids.

Change-Id: Ie31f1f6cb9e5bbc9146088bd820cf80ebf41d757
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=886786
Signed-off-by: Ravi Nori <rnori@redhat.com>