Test 403 error title

Change-Id: I0e2079e485e6e668186cb477027573d9b0adb161
Document size limits

Change-Id: I4327593fc970bd977d9fb2c48ab9eafd5586f1d0
Disable eventlet monkey-patching of DNS

This change avoids eventlet's monkey-patching of DNS resolution.
eventlet's doesn't support IPv6, for example.

The way to avoid eventlet's DNS is to set an environment
variable. The trick is the environment variable needs to be set
before eventlet is imported.

A similar change was made in nova, so this is just copying that
code and technique to Keystone.

This allows re-enabling the IPv6 tests, too.

Change-Id: I1e4d4bbfea374d386796d1505a602fd187e75c67
Revert "Set EVENTLET_NO_GREENDNS=yes in tox.ini."

We don't need this since EVENTLET_NO_GREENDNS=yes is set in
keystone.common.wsgi_server .

This reverts commit 46b224abf1c6f7c9bd579806f202a019e2695b29.

Change-Id: I96c2c567f68cdd509425245c7772196918b44b44
Fixes a typo

Change-Id: Ie5c5fd482312e44b4253076e9d8ebfe75abed378
Merge "Test 403 error title"
Merge "Disable eventlet monkey-patching of DNS"
Merge "Revert "Set EVENTLET_NO_GREENDNS=yes in tox.ini.""
Merge "Document size limits"
Merge "Fixes a typo"