5732 nightly.sh should use check-paths.out to be useful for .gitignore

after ./nightly.sh illumos.sh and a dmake clobber in a build shell

git status is now more or less clean.

richard@omnis:/home/richard/src/illumos-gate/usr/src$ git status
On branch dev-omnios
Untracked files:
  (use "git add <file>..." to include in what will be committed)

    ../../.reviewboardrc
    ../../bldenv.sh
    ../../closed/root_i386-nd/
    ../../closed/root_i386/
    ../../illumos.sh
    ../../nightly.sh


It took 2.06 seconds to enumerate untracked files. 'status -uno'
may speed it up, but you have to be careful not to forget to add
new files yourself (see 'git help status').
nothing added to commit but untracked files present (use "git add" to track)

richard@omnis:/home/richard/src/illumos-gate/usr/src$ find . -name 'check-*.out'
./check-i386.out
./check-paths.out