Fix auth bug with S3 in cn-north-1 region
Merge branch 'cn-north-1-fix' into develop

* cn-north-1-fix:
  Fix auth bug with S3 in cn-north-1 region
Fix bug in error handler when response is None

Regression introduced in #298.
Merge branch 's3-error-fix' into develop

* s3-error-fix:
  Fix bug in error handler when response is None
Remove GetRecords operation from pagination config

Synced with upstream.
Merge branch 'kinesis-page' into develop

* kinesis-page:
  Remove GetRecords operation from pagination config
Bumping version to 0.50.0
Merge branch 'release-0.50.0' into develop

* release-0.50.0:
  Bumping version to 0.50.0
Use get_config_variable instead of profile attr

session.get_config_variable('profile') != session.profile.

In the case of "--profile", we set the session.profile attr,
but in the case of the env var, we look it up when we create
the scoped config or when we call get_config_variable('profile').

I think this can probably be fixed such that we always set
session.profile, but this fixes the immediate issue of
aws/aws-cli#805.
Fix ec2 ModifyVolumeAttribute model

`AutoEnableIO` is AttributeBooleanValue type, not Boolean type.

Fixes aws/aws-cli#803
Merge branch 'profile-env-var' into develop

* profile-env-var:
  Use get_config_variable instead of profile attr
Add endpoint heuristics module

This module will take input data (service_name, region_name, etc)
and construct a complete URL.
Move data loader over to component locator object
Integrate endpoint heuristics into botocore
Remove _regions from botocore
Merge branch 'expect-100' into develop

* expect-100:
  Remove check for service name in s3
  Reset response class when not handling expect 100 continue
  Fix py3 test failure
  Fix failing tests
  Also support HTTP with expect 100 continue
  Initial commit of expect 100-continue support
Sync with the latest ec2 model
Merge branch 'quiver-fix-ec2-modify-volume-attribute-model' into develop

* quiver-fix-ec2-modify-volume-attribute-model:
  Sync with the latest ec2 model
  Fix ec2 ModifyVolumeAttribute model
Merge branch 'endpoint-rules' into develop

* endpoint-rules:
  Remove _regions from botocore
  Integrate endpoint heuristics into botocore
  Move data loader over to component locator object
  Add endpoint heuristics module
Fix failing test from endpoint heuristics

Use the endpoint resolver to find the region name override.
Otherwise it's possible that a ``None`` value can be passed
as a ``region_name`` value to handlers, which we don't want.