net-mgmt/collectd5: fix disk plugin issue for FreeBSD versions 10+
The file lib/collectd/disk.so was being commented out in pkg-plist for
all FreeBSD versions instead of just for versions less than 10.
Reported by: pierre@guinoiseau.eu (via ports-committers@)
Reviewed by: swills (mentor)
Approved by: swills (mentor)
Differential Revision: https://reviews.freebsd.org/D8042