Update lib/generators/kapify/unicorn/templates/unicorn_init.erb

fixed error `initialize': Address already in use - /tmp/mf9.sock (Errno::EADDRINUSE)

1. If there is a pid file, set $ORIG_PID to the file’s contents
2. Send USR2 to current master process, and if successful, then:
   a. Wait for a .oldbin pid file to be created and populated, within defined timeout period
   b. If still within the defined timeout period, wait for a new pid file to be populated and for the .oldbin pid file to be removed
   c. If the new pid file doesn’t exist, or is empty, exit 1, with master failed to start message
   d. If the .oldbin pid value is equal to the new pid file value, exit 1, with master failed to start message
   e. If .oldbin pid still exists after timeout, exit 1, with .oldbin pid still exists message
   f. Output success message, exit 0
3. Else, in case USR2 failed, run Unicorn start task