naemon/utils.c: refactoring of check_file_size

refactored check_file_size to make it easier to read

Signed-off-by: Ricardo Maraschini <ricardo.maraschini@gmail.com>
naemon/utils.c: refactoring and bug fixes on SIGXFSZ signal handler

- refactoring of signal handler for SIGXFSZ signal
- returning if we are unable to get system limits with getrlimit()
  otherwise we gonna fail a few lines below when refering to `rlim'
- removed unnecessary `/dev/null' strcmp() call once it is not a
  regular file, causing check_file_size to return 0

Signed-off-by: Ricardo Maraschini <ricardo.maraschini@gmail.com>
naemon/utils.c: solved indentation bugs

comments changed to something readable by doxigen and some
blank spaces got removed also.

using ./indent.sh now to be sure about the right style.

Signed-off-by: Ricardo Maraschini <ricardo.maraschini@gmail.com>
Merge branch 'ricardomaraschini-utils'