Fix NPE in SystemReader in tests

SystemReader.updateAll() must _not_ test whether the file exists. In
tests at least there are FileBasedConfigs with a null file. Test
configs should (and do) override isOutdated() to deal with this case.

Change-Id: I56303fe0d56afeb9f2203ee807a92c5dcf3809e9
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

org.eclipse.jgit/src/org/eclipse/jgit/util/SystemReader.java

@@ -428,9 +428,6 @@ public abstract class SystemReader {
 		updateAll(config.getBaseConfig());
 		if (config instanceof FileBasedConfig) {
 			FileBasedConfig cfg = (FileBasedConfig) config;
-			if (!cfg.getFile().exists()) {
-				return;
-			}
 			if (cfg.isOutdated()) {
 				LOG.debug("loading config {}", cfg); //$NON-NLS-1$
 				cfg.load();