update_plex_config: Eliminate a potential divide-by-zero.
update_plex_config: Eliminate a potential divide-by-zero.

Tripped-over-by: Karl Pielorz <6b77469d26b4b05f580ba62c684807867ce4533b@tdx.co.uk>

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