EventCommonTPCnv: Generate pair_base dictionaries.

Adjust selection file to generate dictionaries for std:__pair_base classes
needed for persistency.

Event/EventCommonTPCnv/EventCommonTPCnv/OLD_selection.xml

@@ -4,6 +4,7 @@
 
   <class name="INav4MomAssocs_p2" id="8040BEAA-BC65-43B8-B468-A7157C89ACB3" />
   <class name="INav4MomAssocs_p2::Assocs_t" />
-  <class name="INav4MomAssocs_p2::AssocElem_t" />
+  <!-- pick up INav4MomAssocs_p2::AssocElem_t and associated pair_base -->
+  <class pattern="std::*pair*<ElementLink_p2<unsigned int>,*"/>
 
 </lcgdict>

Event/EventCommonTPCnv/EventCommonTPCnv/selection.xml

@@ -18,7 +18,8 @@
 
   <class name="INav4MomAssocs_p3" id="455AEE6B-9834-4E72-8F81-2532A52E3BE7" />
   <class name="INav4MomAssocs_p3::Assocs_t" />
-  <class name="INav4MomAssocs_p3::AssocElem_t" />
+  <!-- pick up INav4MomAssocs_p3::AssocElem_t and associated pair_base -->
+  <class pattern="std::*pair*<ElementLink_p3<unsigned int>,*"/>
 
   <class name="INav4MomLinkContainer_p1" id="A7F0A4C5-F343-4724-B317-FB5A890355FA" />
   <class name="IParticleLinkContainer_p1" id="E82C71AF-AC5C-453B-9A35-FA45A849838E" />