kns: show the release date if the version isn't available

CCBUG: 417192

libdiscover/backends/KNSBackend/KNSResource.cpp

@@ -140,12 +140,13 @@ int KNSResource::size()
 
 QString KNSResource::installedVersion() const
 {
-    return m_entry.version();
+    return !m_entry.version().isEmpty() ? m_entry.version() : m_entry.releaseDate().toString();
 }
 
 QString KNSResource::availableVersion() const
 {
     return !m_entry.updateVersion().isEmpty() ? m_entry.updateVersion()
+         : m_entry.updateReleaseDate().isEmpty() ? m_entry.updateReleaseDate().toString()
          : !m_entry.version().isEmpty() ? m_entry.version()
          : releaseDate().toString();
 }