Change CFA to be a LoadAddress instead of HostAddress

[ribrdb]

Summary

The computed CFA is an address in the target process, not lldb. So printing variables which reference the CFA results in a crash.
See http://llvm.org/bugs/show_bug.cgi?id=21118

[ribrdb]

Not sure if this worked since I wasn't subscribed to the mailing list.

[jasonmolenda]

LGTM.

[jasonmolenda]

Landed in r219896

source/Expression/DWARFExpression.cpp

                 if (cfa != LLDB_INVALID_ADDRESS)
                 {
                     stack.push_back(Scalar(cfa));
-                    stack.back().SetValueType (Value::eValueTypeHostAddress);
+                    stack.back().SetValueType (Value::eValueTypeLoadAddress);
                 }
                 else
                     if (error_ptr)