Migrate salt.cloud.exceptions to salt.exceptions

This means that we no longer have to load salt.cloud when calling the
salt cli and paves the way for additional sandboxing of salt-cloud to avoid
unecessary imports.
Remove what seem to be unused imports.
Fix tests and lint
Missed one lint
Bring boto modules from develop to 2014.7
Bring boto states from develop to 2014.7
Bring boto module tests from develop to 2014.7
Bring boto state tests from develop to 2014.7
Merge pull request #15479 from cachedout/no_cloud

Migrate salt.cloud.exceptions to salt.exceptions
Merge pull request #15490 from basepi/backport_boto

Backport boto modules/states/tests
Merge branch '2014.7' into develop