Unbreak sysutils/pc-networkmanager

This is part of the TrueOS tools, and it was marked BROKEN about
a year ago; a fix appeared upstream only days later, but there's
been no udpate to the port.

The same kind of fix probably applies to sysutils/pcbsd-utils-qt5
but I don't feel like chasing it. PR listed below is for that port,
pinging maintainer(s).

(All this is because we're chasing fallout for the Qt 5.13 update)

PR: 231682