CommitBuilder: Deprecate setEncoding(String)

Deprecate the method in favor of setEncoding(Charset).

Update the only caller in the code base that was still using
the deprecated variant.

Change-Id: I6357f2d0c727007013c72e9d5b7c72a3f5f3f2b1
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/T0003_BasicTest.java

@@ -538,7 +538,7 @@ public class T0003_BasicTest extends SampleDataRepositoryTestCase {
 				4294967295000L, 60));
 		commit.setCommitter(new PersonIdent("Joe Hacker", "joe2@example.com",
 				4294967295000L, 60));
-		commit.setEncoding("ISO-8859-1");
+		commit.setEncoding(ISO_8859_1);
 		commit.setMessage("\u00dcbergeeks");
 		ObjectId cid = insertCommit(commit);
 		assertEquals("2979b39d385014b33287054b87f77bcb3ecb5ebf", cid.name());

org.eclipse.jgit/src/org/eclipse/jgit/lib/CommitBuilder.java

@@ -295,7 +295,9 @@ public class CommitBuilder {
 	 * @param encodingName
 	 *            the encoding name. See
 	 *            {@link java.nio.charset.Charset#forName(String)}.
+	 * @deprecated use {@link #setEncoding(Charset)} instead.
 	 */
+	@Deprecated
 	public void setEncoding(String encodingName) {
 		encoding = Charset.forName(encodingName);
 	}