Don't set unnamed_addr in CreateRuntimeVariable.

This was fairly broken. For example,

@__dso_handle would or would not get an unnamed_addr depending on how many
global destructors were used in a translation unit.

The consensus was that not every runtime variable is unnamed_addr and that
__dso_handle handle should not be, so just don't add unnamed_addr in
CreateRuntimeVariable.

llvm-svn: 209484