[PATCH 10/25] Fix initialization order

Fix GCC warnings like:

In file included from src/NCollection/NCollection_BaseVector.cxx:6:0:
inc/NCollection_BaseVector.hxx: In constructor ‘NCollection_BaseVector::MemBlock::MemBlock(NCollection_BaseAllocator*)’:
inc/NCollection_BaseVector.hxx:65:36: warning: ‘NCollection_BaseVector::MemBlock::myAlloc’ will be initialized after [-Wreorder]
inc/NCollection_BaseVector.hxx:62:34: warning: ‘Standard_Integer NCollection_BaseVector::MemBlock::myFirstInd’ [-Wreorder]
inc/NCollection_BaseVector.hxx:39:5: warning: when initialized here [-Wreorder]
inc/NCollection_BaseVector.hxx: In constructor ‘NCollection_BaseVector::MemBlock::MemBlock(Standard_Integer, Standard_Integer, NCo

Contributed by: Thomas Paviot, Author