Rename jvm.dir to jvm-dir

This will eventually be written to "cfg.jvm-dir", so we don't want the
extra dot in the name.

src/main/java/org/scijava/launcher/Java.java

@@ -338,7 +338,7 @@ public static void upgrade(BiConsumer<String, Double> subscriber)
 						Log.debug(exc);
 					}
 				}
-				Config.update(configFile, "jvm.dir", newJavaPath.toString());
+				Config.update(configFile, "jvm-dir", newJavaPath.toString());
 			}
 		}