Add entries to .gitignore for m2e settings/preference files

Change-Id: Ie70c285440b6200ad7f4dd8dea8a97317e1e62fc
diff --git a/gerrit-gwtdebug/.gitignore b/gerrit-gwtdebug/.gitignore
index 903c6c8..194bedc 100644
--- a/gerrit-gwtdebug/.gitignore
+++ b/gerrit-gwtdebug/.gitignore
@@ -2,3 +2,4 @@
 /.classpath
 /.project
 /.settings/org.maven.ide.eclipse.prefs
+/.settings/org.eclipse.m2e.core.prefs
\ No newline at end of file