fwget: Simplify logic

Summary:
Use log() to print messages that should be supressed when -q is in use.

No functional changes intended.

Differential Revision: https://reviews.freebsd.org/D48393
Reviewed By: manu
Sponsored by: Rubicon Communications, LLC ("Netgate")

(cherry picked from commit fb98fc4755def2cb8ca145751b0e54485d5e2f4a)