[CLIENT-1854] Python client crashes while doing IO during server upgrade/downgrade

[rpandian-spike]

Addresses the following:

CLIENT-1854 | Python client crashes while doing IO during server upgrade/downgrade
(https://aerospike.atlassian.net/browse/CLIENT-1854)

[juliannguyen4]

@rpandian-spike I had some concerns about this PR and I was hoping you could address them.

1. This is a breaking change because we are changing the behavior of the client constructor, and customers might have code that doesn't check for exceptions if a client is created (in the docs, the client shouldn't throw an exception). If we make this change, then we would have to raise the version to 8.0.0.
2. Another issue is when customers try to close and reopen a connection by calling connect(). How should we handle that case?

Alternatively, we could just leave the client constructor code as it is and add a check for a connection before each server operation to prevent a segfault. I prefer this approach since it isn't a breaking change.

[juliannguyen4]

P.S We should also move the changes related to CLIENT-1829 to a different PR, since this PR already addresses CLIENT-1854

[rpandian-spike]

With this new change, Connect and Close calls are no-ops

[rpandian-spike]

1829 and 1854 are different use cases but same issue

[dwelch-spike]

Some comments and questions.