Fix style(9) a bit and ensure that error from initializing kqueue(2) is
sane

• Push the kqueue(2) initialization down so the errno will correspond with the failure instead of potentially being stomped on by functions called by PLAIN_REQUIRE_KERNEL_MODULE
• Delete trailing whitespace
• Add spaces between braces for conditional and control blocks (for/if)
• Use err/errx instead of perror+printf+exit/printf+exit.
• Remove braces for single-line conditionals

Tested with and without -DDEBUG

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division