check_load: add alternative uptime syntax

check_load parses load from the uptime command if no proc filesystem is available. Seems
like there are at least 2 different uptime outputs.

linux:
 20:44:34 up 25 days,  2:07, 13 users,  load average: 0.13, 0.17, 0.22

freebsd 8:
 8:44PM  up  4:29, 1 user, load averages: 0.00, 0.00, 0.00

plugins/check_load.c

@@ -153,7 +153,16 @@ main (int argc, char **argv)
 		printf (_("Could not open stderr for %s\n"), PATH_TO_UPTIME);
 	}
 	fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_process);
-	sscanf (input_buffer, "%*[^l]load average: %lf, %lf, %lf", &la1, &la5, &la15);
+    if(strstr(input_buffer, "load average:")) {
+	    sscanf (input_buffer, "%*[^l]load average: %lf, %lf, %lf", &la1, &la5, &la15);
+    }
+    else if(strstr(input_buffer, "load averages:")) {
+	    sscanf (input_buffer, "%*[^l]load averages: %lf, %lf, %lf", &la1, &la5, &la15);
+    }
+    else {
+		printf (_("could not parse load from uptime: %s\n"), result, PATH_TO_UPTIME);
+		return STATE_UNKNOWN;
+    }
 
 	result = spclose (child_process);
 	if (result) {