avoid 100% cpu usage, die when PID file cannot be created

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@3702 2b470e98-0d58-463d-a4d8-8e2adae1ed80

fhem/contrib/PRESENCE/presenced

@@ -118,7 +118,7 @@ if($opt_h)
 }
 
 
-open(PIDFILE, ">$opt_P");
+open(PIDFILE, ">$opt_P") or die("Could not open PID file $opt_P: $!");
 print PIDFILE $$."\n";
 close PIDFILE;
 
@@ -380,7 +380,7 @@ local $SIG{HUP} = sub {$nextrun = gettimeofday();};
 				    }
 				}
 	
-			
+			sleep 0.1;
 		}
 	}
 }