qbs updates.

- Make project files buildable with current qbs.
- Update qbs submodule to enable Qt Creator to open these project files.
- Fix an invalid access that caused a soft assert.

Change-Id: I976d19240112d1ff048e51036e6702383735352b
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

qbs/pluginspec/pluginspec.qbs

@@ -1,4 +1,5 @@
 import qbs.base 1.0
+import qbs.TextFile
 import qbs.fileinfo as FileInfo
 
 Module {

src/app/app_version_header.qbs

@@ -1,4 +1,5 @@
 import qbs
+import qbs.TextFile
 
 Product {
     name: "app_version_header"

src/plugins/qbsprojectmanager/qbsnodes.cpp

@@ -489,7 +489,7 @@ void QbsProductNode::setQbsProductData(const qbs::ProductData prd)
     if (m_qbsProductData == prd)
         return;
 
-    bool productWasEnabled = m_qbsProductData.isEnabled();
+    bool productWasEnabled = m_qbsProductData.isValid() && m_qbsProductData.isEnabled();
     bool productIsEnabled = prd.isEnabled();
     bool updateExisting = productWasEnabled != productIsEnabled;