Revert SSL commits.

This commit reverts these commits:

ebe679f56c5b4c95744b9da06a05917e61ac50e3
3037f07d78755d0f8aa6e54f2088d8117ff192c7
9e53fcfa8be0914d565d6968cb02c0342fbd2675
11615b4240244b38141b3d04000dc77bbdc22810
ddb3aea95f074f9a5f538df19cb515f5f8c7a8a4
30667861b623dd64152cfa51f838e683c515743c
ae880628260972002d8f5d0d4c36e856ff252d2d
f29576f7c7e1c8a3b0000ce06615de640446e26c
62714883a84896b168a7768e84f74c42664d2958
82955ab7d78463a29cd8112d4872ffcc73d9fd0c
bfa554fc7e02dea390466f168e3715ac6e002267
69d77139ffe33aecda166b93c3c4f8535032f1d2
0910683d8f5946f9f44c87f881957b91633fe83a
73fcdb756834cd985668a127c8a7191513c2e913
ad374aad95a138c5b6189b3d732d2ef434fafa54
994aacf94573db6e3c39413e34bac233a8abedeb
fcf4bf13ce2b4e228af3df7e34ff6fddec2aa9a1
020a1659748eff46dcbdc714c051b68ff1e86548
e8e7a287a2e0ad9596ded7075f2e4f03452c8bb1
507f4e753acbc1d9f283a8e621171ee80bdd986b
4262a58df018aa2ad3923cda6f90d4a8a50ca60a
62599598c36b6fab90d70d8db35df8ba4e45bf41
f25fe077c9b3842218d1a4ec63c90e5f6aa11890
3ce2e785f236e7fa8d9f5a98b7da4502120fe73c
b3b9d04365705aa25ace6e1097a23b579d3d3593
1113590 - Nodes requires Pulp's cert to be trusted
1112906 - pulp-admin requires Pulp's cert to be trusted
1112904 - pulp-consumer requires Pulp's cert to be trusted

This commit addresses three bugs:

[0] - Nodes wasn't checking the signature on the Parent Pulp server
against a list of trusted certificate authorities. This commit
introduces that check, as well as a new nodes.conf pair of settings to
either disable the check or change where the certificate pack is stored.

[1] - pulp-admin also had the same issue as Nodes, and it now also has
similar settings in admin.conf.

[2] - pulp-consumer was also affected by this same security issue.
Similar settings are introduced in consumer.conf with this commit.

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1113590
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1112906
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1112904
Fixes in response to PR review.
Merge branch 'rbarlow-ssl_verify_option' into pulp-2.4

Conflicts:
	docs/sphinx/user-guide/installation.rst
	docs/sphinx/user-guide/release-notes/2.4.x.rst
	server/etc/pulp/server.conf