Add guessed dependencies to OBJS after bsd.dep.mk in case of it adding to SRCS.

This was a regression in r295985.

bsd.dep.mk adds to SRCS for dtrace probes, yacc grammars and some
others.

The code that is moving is planned to be removed once FAST_DEPEND is
default (and the only option) though since FAST_DEPEND doesn't use this.

Pointyhat to: bdrewery
Sponsored by: EMC / Isilon Storage Division