library: uptime API changes

Removed the printf_uptime, binaries can do printf easily enough.
sprint_uptime split into two as there wasn't a lot of common
code
 sprint_uptime(): old style uptime line
 sprint_uptime_short(): short new style "uptime -p"

Hertz_hack needed this, no sane system uses the code (I think)
so just assume 100 like we do in FreeBSD.

proc/libprocps.sym

@@ -57,8 +57,10 @@ global:
 	strtosig;
 	tty_to_dev;
 	unix_print_signals;
-	uptime;
 	user_from_uid;
+	uptime;
+	sprint_uptime;
+	sprint_uptime_short;
 	procps_linux_version;
 	procps_meminfo_new;
 	procps_meminfo_read;