Do not arbitrarily create directories

The JsonSchemaManager force-created a "json" directory, even in the
installation resource path. This is unnecessary and ugly, because it
creates that even within the Qt Creator installation from e.g. the
online installer, which results in directories being left over when
uninstalling it.

Change-Id: I5c683353b124c219c5f065209212a84a4c7ccd0f
Reviewed-by: Marco Benelli <marco.benelli@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/utils/json.cpp

@@ -671,7 +671,7 @@ JsonSchemaManager::JsonSchemaManager(const QStringList &searchPaths)
 {
     foreach (const QString &path, m_searchPaths) {
         QDir dir(path);
-        if (!dir.exists() && !dir.mkpath(path))
+        if (!dir.exists())
             continue;
         dir.setNameFilters(QStringList(QLatin1String("*.json")));
         foreach (const QFileInfo &fi, dir.entryInfoList())