Fix typo (unused import that breaks build)

Author: sevaseva

java/client/src/org/openqa/selenium/firefox/FirefoxDriver.java

@@ -29,8 +29,6 @@
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 
-import com.sun.javafx.runtime.SystemProperties;
-
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.OutputType;
 import org.openqa.selenium.Platform;