COFF: Improve section hash value.
COFF: Improve section hash value.

std::distance(C->Relocs.end(), C->Relocs.begin()) is the same as NumRelocs
which is already added to the hash value. What we are missing here is the
section size.

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@248202 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld