Move do_sleep() from helper.c --> util.c

This move makes it possible to share the code between the Finit daemon
and its client tools.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

helpers.h

@@ -63,7 +63,6 @@ int     print_result    (int fail);
 void    logit           (int prio, const char *fmt, ...);
 
 int     start_process   (char *cmd, char *args[], int console);
-void    do_sleep        (unsigned int sec);
 int     getuser         (char *username, char **home);
 int     getgroup        (char *group);
 void    set_hostname    (char **hostname);