ssh_auth: detect when source file has 0 valid keys

If an improperly-formatted file is used as the source file for an
ssh_auth.present state, the state incorrectly reports that all keys in
the file are present. This is because the functions that check the
source file only return keys that need to be changed, and with no valid
keys, there is nothing to change.

This commit detects when there are no valid keys found, and reports this
in the state output.

Additionally, since one of the ways that this edge case can be triggered
is if a public key from PuTTYgen is used, instructions have been added
to the ssh_auth.present docstring explaining how to obtain the
OpenSSH-compatible public key for the corresponding private key
generated by PuTTYgen.

Fixes #6277.
Limit pkg.latest to 1 refresh per run unless overridden

This fixes #6292 by moving the rtag check to the call to
pkg.latest_version, and never refreshing if/when pkg.install is run.
cmd_iter_no_block did not pass on tgt to get_iter_returns(). That makes the
saltmaster always query ALL minions with saltutil.find_job because
get_iter_returns default to tgt='*'.
yum: Allow 32bit pkgs in arches other than i686

The yum providers previously only supported 32bit packages that were for
the i686 architecture. This adds support for any iX86 arch.

Fixes #6299.
Fix minion traceback when pillar SLS is malformed

When pillar data is rendered for use by pillar.get, SLS that does not
render to a dictionary results in a traceback on the minion. This commit
resolves that traceback.

Fixes #5910.

Conflicts:
	salt/pillar/__init__.py
Update mysql docstrings to reflect new features