Changes for CREAM packaging

Changes for EMI-3

• The package glite-build-common-cpp is deprecated since the CREAM team has dropped the support for M4 macros. The new build time dependency to be taken into consideration for building C/C++ components is the package emi-pkgconfig-compat. The package contains the pkg-config metadata files for all those external dependencies which don't support pkg-config, for example classad or boost. The package is published via EMI YUM repositories.