Add locale to the properties manageable by SystemReader

Change-Id: I5e9af40d38bb671cb9fcdb0fa3b4eb3af5f36f6c

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/MockSystemReader.java

 import java.io.File;
 import java.io.IOException;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.TimeZone;
 
 	public TimeZone getTimeZone() {
 		return TimeZone.getTimeZone("GMT-03:30");
 	}
+
+	@Override
+	public Locale getLocale() {
+		return Locale.US;
+	}
 }

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

 import java.io.File;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.util.Locale;
 import java.util.TimeZone;
 
 import org.eclipse.jgit.lib.Config;
 		public TimeZone getTimeZone() {
 			return TimeZone.getDefault();
 		}
+
+		@Override
+		public Locale getLocale() {
+			return Locale.getDefault();
+		}
 	};
 
 	/** @return the live instance to read system properties. */
 	 * @return system time zone, possibly mocked for testing
 	 */
 	public abstract TimeZone getTimeZone();
+
+	/**
+	 * @return the locale to use
+	 */
+	public abstract Locale getLocale();
 }