Added nightly script used for regression testing on macchapel-mac.  The cron entry is slightly different than on other machines to avoid an occasional failure of the 'svn update' command.  Despite having installed a new version of svn on this machine, occasionally the svn update fails and the repository needs to be cleaned or destroyed and checked out from scratch.  To avoid running into this situation, the cron entry blows away the readonly copy of chapel just before running nightly.  In this case, the nightly script checks out a clean copy instead of updating the old copy.  Here is what the cron entry looks like today:
Added nightly script used for regression testing on macchapel-mac.  The cron
entry is slightly different than on other machines to avoid an occasional
failure of the 'svn update' command.  Despite having installed a new version of
svn on this machine, occasionally the svn update fails and the repository needs
to be cleaned or destroyed and checked out from scratch.  To avoid running into
this situation, the cron entry blows away the readonly copy of chapel just
before running nightly.  In this case, the nightly script checks out a clean
copy instead of updating the old copy.  Here is what the cron entry looks like
today:

  10 0 * * * rm -rf /tmp/chapel-cron-chapelu-readonly
  15 0 * * * /Users/chapelu/chapel/util/cron/nightly.macchapel-mac


git-svn-id: 88467cb1fb04b8a755be7e1ee1026be4190196ef@17345 3a8e244f-b0f2-452b-bcba-4c88e055c3ca

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