[BProc] bug in bproc.h for BProc 3.1.9

[Jag <ag...@li...>]

I just noticed a bug in the /usr/include/sys/bproc.h file for BProc
3.1.9  Apparently the _bproc_vrfork() function became
_bproc_vrfork_io(), however the header file was never adjusted to
represent this.  So, the header files mentioned a _bproc_vrfork() which
doesn't exist, and doesn't mention the actual function,
_bproc_vrfork_io()

Sean