Low: asterisk: improve/simplify start

• Move local variables to start of function
• Use $dir, not $i, as the directory name iterator
• Move the "is the directory writable?" check to a more logical location
• Ditch start_wait and simply use "while true" and break
• Simply spin on monitor, rather than spinning on status and then doing a one-shot monitor (monitor calls status anyway)
• Return OCF error codes, rather than arbitrary return codes