Provide /opt/rh/SAP/lib64/libstdc++.so.6 symlink

Merge Request Required Information

Summary of Changes

This adds %post and %postun scriptlets to compat-sap-c++-10 for maintaining a symbolic link at /opt/rh/SAP/lib64/libstdc++.so.6 pointing to the latest compat-sap-c++-N.so (for N >= 10) within that directory (which are provided by corresponding compat-sap-c++-N packages for N >= 10). The two scriptlets are identical, and the intent is that these same scriptlets will added to compat-sap-c++-11 and compat-sap-c++-12 as well.

Scratch builds of compat-sap-c++-10, -11 and -12 with this change for testing purposes can be found at:

https://kojihub.stream.rdu2.redhat.com/koji/taskinfo?taskID=3317091

https://kojihub.stream.rdu2.redhat.com/koji/taskinfo?taskID=3317098

https://kojihub.stream.rdu2.redhat.com/koji/taskinfo?taskID=3317097

Approved Development Ticket

RHEL-7257