Fix x86 targeting compile fail
Fix x86 targeting compile fail

- Added std:: namespace to the metadata map in attribute compiler

Change-Id: I0c93783df0e2a790a762757f8aa5ed47af0f1be1
CQ: SW229583
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/6751
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>

open-power/hostboot,alvintpwang/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot,alvintpwang/hostboot,open-power/hostboot,csmart/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,csmart/hostboot,csmart/hostboot,alvintpwang/hostboot,alvintpwang/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,csmart/hostboot