Revert "entrypoint: Remove unnecessary use of an extended glob."

This reverts commit 0d72546a4c.  The
extended glob matched when the _entire_ value was numeric, whereas
the pattern matches if it _starts_ with a number.

Fixes: #433
Fixes: #435

entrypoint.sh

@@ -89,7 +89,7 @@ setConfigurationValue() {
             [Tt][Rr][Uu][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Nn]one)
             TYPE="bool"
             ;;
-            [1-9][0-9]*)
+            +([0-9]))
             TYPE="integer"
             ;;
             [\[\(]*[\]\)])