Fix range checks for numBorders in CM_AddFacetBevels
Fix range checks for numBorders in CM_AddFacetBevels

adapted from patch by @zturtleman

See https://github.com/ioquake/ioq3/commit/ee2541efee2eace042303197a1645013d22fcc34
See https://github.com/etlegacy/etlegacy/commit/0fa531a3a958a287d424a6e56198ac14fc3aec5c

DaemonEngine/Daemon,DaemonEngine/Daemon,DaemonEngine/Daemon,DaemonEngine/Daemon