prevent "Symbol not found" errors on Mac #6761

[pdurbin]

What this PR does / why we need it:

I was getting errors like this:

(venv) murphy:installer pdurbin$ python testit.py 
Traceback (most recent call last):
  File "testit.py", line 2, in <module>
    import psycopg2
  File "/Users/pdurbin/github/iqss/dataverse/scripts/installer/venv/lib/python3.7/site-packages/psycopg2/__init__.py", line 50, in <module>
    from psycopg2._psycopg import (                     # noqa
ImportError: dlopen(/Users/pdurbin/github/iqss/dataverse/scripts/installer/venv/lib/python3.7/site-packages/psycopg2/_psycopg.cpython-37m-darwin.so, 2): Symbol not found: _PQsslAttribute
  Referenced from: /Users/pdurbin/github/iqss/dataverse/scripts/installer/venv/lib/python3.7/site-packages/psycopg2/_psycopg.cpython-37m-darwin.so
  Expected in: flat namespace
 in /Users/pdurbin/github/iqss/dataverse/scripts/installer/venv/lib/python3.7/site-packages/psycopg2/_psycopg.cpython-37m-darwin.so

Which issue(s) this PR closes:

None

Special notes for your reviewer:

I got this tip from https://stackoverflow.com/a/58443768/19464

After installing the second package, psycopg2-binary, I was able to run the test script and get this output:

(venv) murphy:installer pdurbin$ python testit.py 
(4388, 'DataFile', 'file://1717f8f1341-710ffaf39b55')
(4387, 'Dataset', 'file://10.5072/FK2/Q3LUGL')
(4386, 'Dataverse', None)
(4385, 'DataFile', 'file://1717f8a42b4-272bd20eface')
(4384, 'Dataset', 'file://10.5072/FK2/NURRRR')
(4383, 'Dataverse', None)
(4382, 'DataFile', 'file://1717f7bd76f-0c4d131cb54e')
(4381, 'Dataset', 'file://10.5072/FK2/F9DAPZ')
(4380, 'Dataverse', None)
(4379, 'DataFile', 'file://1717f700b32-15e4e9f6ef7f')
(venv) murphy:installer pdurbin$ 

Suggestions on how to test this:

Here's the test script from @landreev

#!/usr/bin/env python3
import psycopg2
import os
Host = "localhost"
Port = 5432
Database = "dvndb"
Username = "dvnapp"
Password = "secret"
conn_string = "host='"+Host+"' dbname='"+Database+"' user='"+Username+"' password='"+Password+"'"
conn = psycopg2.connect(conn_string)
cursor = conn.cursor()
dataverse_query="SELECT id, dtype, storageidentifier FROM dvobject ORDER BY id DESC LIMIT 10"
cursor.execute(dataverse_query)
records = cursor.fetchall()
for rec in records:
    print(rec)

Does this PR introduce a user interface change?:

No

Is there a release notes update needed for this change?:

No

Additional documentation:

No

[coveralls]

Coverage remained the same at 19.661% when pulling 3b0dcfa on 6761-psycopg2 into ed5a575 on 6761-payara-installer-update.

[landreev]

I don't think you installed a "second package" - you installed psycopg2-binary, instead of building psycopg2 from sources. It's not an additional requirement, is what I'm trying to say.
I don't think it makes sense to have both in the requirements.txt. It should be one of the two, and then maybe a line in README_python.txt, saying that "if you're having trouble getting psycopg2 to work, consider installing [the other] instead."
Maybe the binary version should be our first choice though. Because it's more likely to work for more people? (but I don't think it's guaranteed to work for everyone/on all distributions).

From https://pypi.org/project/psycopg2-binary/:
The binary package is a practical choice for development and testing but in production it is advised to use the package built from sources.

[landreev]

I'm just going to take it and edit as needed. thanks.