templates: check for mode 640 in permissions

Thanks to Nick Warne <nick@linicks.net> for the suggestion.
*.SlackBuild: Add "-L" to the permissions-fixing find invocation

  From: Serg Bormant <bormant@gmail.com>
  Subject: [Slackbuilds-users] [BUG] SlackBuild templates
  Date: Fri, 21 Dec 2012 11:58:32 +0400

  Hi,

  Consider something like this in source tarball:

  $ mkdir test; cd test
  $ mkdir docs; touch docs/README docs/COPYING
  $ ln -s docs/* .
  $ ls -o *
  lrwxrwxrwx 1 user   12 Dec 21 11:45 COPYING -> docs/COPYING
  lrwxrwxrwx 1 user   11 Dec 21 11:45 README -> docs/README

  docs:
  total 0
  -rw-r--r-- 1 user 0 Dec 21 11:45 COPYING
  -rw-r--r-- 1 user 0 Dec 21 11:45 README

  *.SlackBuild templates offer this to sanitize permissions:

  find . \
   \( -perm 777 -o -perm 775 -o -perm 711 -o -perm 555 -o -perm 511 \) \
   -exec chmod 755 {} \; -o \
   \( -perm 666 -o -perm 664 -o -perm 600 -o -perm 444 -o -perm 440 -o -perm
  400 \) \
   -exec chmod 644 {} \;

  But -perm 777 will fire on symlinks and will set  eXecutable permissions to
  docs/COPYING and docs/README.

  Using "find -L ..." or "... ! -type l ..." can help to avoid this.
*-template.SlackBuild: Fix "find -L ." usage

Thanks to willysr for pointing out my thinko.