Don't die if Device::Serialport is not installed, just cry.

git-svn-id: https://fhem.svn.sourceforge.net/svnroot/fhem/trunk/fhem@1713 2b470e98-0d58-463d-a4d8-8e2adae1ed80

FHEM/DevIo.pm

@@ -159,11 +159,19 @@ DevIo_OpenDev($$$)
 
 
     if ($^O=~/Win/) {
-     require Win32::SerialPort;
+     eval {
-     $po = new Win32::SerialPort ($dev);
+       require Win32::SerialPort;
+       $po = new Win32::SerialPort ($dev);
+     }
     } else  {
-     require Device::SerialPort;
+     eval {
-     $po = new Device::SerialPort ($dev);
+       require Device::SerialPort;
+       $po = new Device::SerialPort ($dev);
+     }
+    }
+    if($@) {
+      Log 1, $@;
+      return $@;
     }
 
     if(!$po) {