Corrected shared library names that got the .abi3 suffix for python-36 and up after devel/py-cffi upgrade to 1.11.2

This is the followup for the r457997 commit that updated devel/py-cffi to 1.11.2.
As it turned out, the shared object names built by py-cffi has changed in python 36.
Dependent ports can choose between installing such shared object as part of their plist, or
generating them in the runtime and placing them into ~/.cache/{port-name}/ The former ones,
that include the shared objects in their plist, got affected.

4 of the ports were failing explicitly in their py36 flavor during the strip phase.
The other 6 were either missing strip entirely, or performed the strip operation without
using explicit shared object names. These 6 ports didn't trigger any build errors, and were
failing silently during the runtime, making the problem very hard to detect.

Precisely, .abi3 suffix is now added for the py36 flavor of relevant ports.

Here are the 10 ports that got affected and are now corrected:
databases/py-psycopg2cffi devel/py-pygit2 devel/py-xattr devel/py-pyopencl devel/py-atomiclong
multimedia/py-librtmp net/py-nnpy security/py-bcrypt security/py-cryptography security/py-pynacl

All of them got the * in the stripped shared object name, and a PORTREVISION bump.