Update JmeVersion.java

If the properties file is missing, it will actually crash with an NPE instead of an IO exception. continue as original intended.

Exception in thread "main" java.lang.ExceptionInInitializerError
	at com.jme3.system.AppSettings.<clinit>(AppSettings.java:222)
	at com.jme3.app.SimpleApplication.start(SimpleApplication.java:113)
	at Test.main(Test.java:12)
Caused by: java.lang.NullPointerException: while trying to invoke the method java.io.Reader.read(char[]) of a null object loaded from field java.util.Properties$LineReader.reader of an object loaded from local variable 'this'
	at java.util.Properties$LineReader.readLine(Properties.java:450)
	at java.util.Properties.load0(Properties.java:369)
	at java.util.Properties.load(Properties.java:357)
	at com.jme3.system.JmeVersion.<clinit>(JmeVersion.java:51)
	... 3 more

jme3-core/src/main/java/com/jme3/system/JmeVersion.java

@@ -49,7 +49,7 @@ public class JmeVersion {
     static {
         try {
             props.load(JmeVersion.class.getResourceAsStream("version.properties"));
-        } catch (IOException ex) {
+        } catch (Exception ex) {
             logger.log(Level.WARNING, "Unable to read version info!", ex);
         }
     }