SW-826: adding Casacore.casa as dependency on LCS/Common makes many lofar libs...

SW-826: adding Casacore.casa as dependency on LCS/Common makes many lofar libs dependend on 3rd party libs which we don't actually use. This hinders us in deployment and maintenance on various systems. Hence, I removed the hard dependency on Casacore.casa, and made the empty-stub-CasaLogSink print out a warning message.

LCS/Common/CMakeLists.txt

@@ -3,7 +3,7 @@
 lofar_package(Common 3.3)
 
 include(LofarFindPackage)
-lofar_find_package(Casacore COMPONENTS casa)
+# lofar_find_package(Casacore COMPONENTS casa)
 lofar_find_package(Boost REQUIRED)
 lofar_find_package(Readline)
 

LCS/Common/src/CasaLogSink.cc

@@ -108,7 +108,9 @@ namespace LOFAR {
 
 #else
   void CasaLogSink::attach()
-  {}
+  {
+    cout << "WARNING: no casa logging available." << endl;
+  }
 #endif
 
 } // end namespaces