Fix erroneous complaint from github actions

Shellcheck in github actions is giving false positive
for unreachable code.

Signed-off-by: Tero Tervala <tero.tervala@unikie.com>

githooks/check-commits.sh

@@ -9,6 +9,9 @@ SDIR="$(realpath "$SDIR")"
 TMPF="/tmp/TEMP.MSG"
 
 function On_exit {
+    # My shellcheck did not complain, however github actions shellcheck did.
+    # Complaint was that this code is unreachable, it is actually reachable.
+    # shellcheck disable=SC2317
     rm -f "$TMPF"
 }