When using sysinstall on a running system and editing a disk label fails, suggest setting kern.geom.debugflags to 16.
When using sysinstall on a running system and editing a disk label
fails, suggest setting kern.geom.debugflags to 16.

PR:		bin/94409
Submitted by:	Markus Oestreicher <m punkt oe at x dash trader dot de>
MFC after:	10 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase