Replace SysPropsTest with VersionUtilTest.

As pointed out by soapyfrog, depending on info from the JVM running the
test is fragile and not a good idea.

Fixes #84.

src/test/java/com/threerings/getdown/util/VersionUtilTest.java

@@ -3,27 +3,27 @@
 // Copyright (C) 2004-2016 Getdown authors
 // https://github.com/threerings/getdown/blob/master/LICENSE
 
-package com.threerings.getdown.data;
+package com.threerings.getdown.util;
 
 import org.junit.Test;
 
 import static org.junit.Assert.assertTrue;
 
-public class SysPropsTest
-{
+public class VersionUtilTest {
+
     @Test
     public void shouldParseJavaVersion ()
     {
-        long version = SysProps.parseJavaVersion(
-            "java.version", "(\\d+)\\.(\\d+)\\.(\\d+)(_\\d+)?");
+        long version = VersionUtil.parseJavaVersion(
+            "(\\d+)\\.(\\d+)\\.(\\d+)(_\\d+)?", "1.8.0_152");
         assertTrue(version > 1060000);
     }
 
     @Test
     public void shouldParseJavaRuntimeVersion ()
     {
-        long version = SysProps.parseJavaVersion(
-            "java.runtime.version", "(\\d+)\\.(\\d+)\\.(\\d+)(_\\d+)?(-b\\d+)?");
+        long version = VersionUtil.parseJavaVersion(
+            "(\\d+)\\.(\\d+)\\.(\\d+)(_\\d+)?(-b\\d+)?", "1.8.0_131-b11");
         assertTrue(version > 106000000);
     }
 }