Unbreak the port for users of -Werror -- the code stopped qualifying
for WARNS=3 a while ago, because it relies on implicit copy-constructors,
which are deprecated in some cases since c++11.

Fix another kind of warning by correcting the indentation.

No PORTREVISION bump because the changes are superficial -- resulting
binary remains the same.

Reported by: pkg-fallout
Tested with: llvm10