SimpleDataSource: Fix implicit usage of system default charset

ErrorProne reports:

  [DefaultCharset] Implicit use of the platform default charset,
  which can result in differing behaviour between JVM executions
  or incorrect behavior if the encoding of the data source doesn't
  match expectations.

Change-Id: Iff35e84286d7d725350fe862d77e351fedd435cd

src/main/java/com/google/gwtorm/jdbc/SimpleDataSource.java

diff --git a/src/main/java/com/google/gwtorm/jdbc/SimpleDataSource.java b/src/main/java/com/google/gwtorm/jdbc/SimpleDataSource.java
index abefb66..dcf1e61 100644
--- a/src/main/java/com/google/gwtorm/jdbc/SimpleDataSource.java
+++ b/src/main/java/com/google/gwtorm/jdbc/SimpleDataSource.java
@@ -14,7 +14,11 @@
 
 package com.google.gwtorm.jdbc;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import java.io.BufferedWriter;
 import java.io.File;
+import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.net.MalformedURLException;
 import java.net.URL;
@@ -85,7 +89,7 @@
       driver = null;
     }
 
-    logWriter = new PrintWriter(System.out);
+    logWriter = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out, UTF_8)));
   }
 
   private static SQLException badClasspath(final String classpath, final MalformedURLException e1) {