Json: Fix indenter for json files.

Change-Id: Id864509dd78a70fc34a3798b80f7e1c8991181f4
Reviewed-on: http://codereview.qt-project.org/6038
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@nokia.com>

src/libs/qmljs/qmljscodeformatter.cpp

@@ -90,6 +90,7 @@ void CodeFormatter::recalculateStateAfter(const QTextBlock &block)
             switch (kind) {
             case Identifier:    enter(objectdefinition_or_js); continue;
             case Import:        enter(top_qml); continue;
+            case LeftBrace:     enter(top_js); enter(expression); continue; // if a file starts with {, it's likely json
             default:            enter(top_js); continue;
             } break;