Fix for bug #9128: issue with salt-master ttys with lvdisplay command

lvdisplay checks the file flags of the ttys file descriptors.
Currently all three stds file descriptor are set write only.

This fix :
+ set stdin as read only
+ set stdout, stderr as write only
Use uppercase for `OS` env variable

This is used for Windows system where this environment variable
is case-insitive. However, if Windows/Cygwin is used, Python
is case-sensitive and the conditions fail.
Add output_loglevel param to cmd.run* functions

Also deprecates the "quiet" param, and alters the logging behavior of
cmd.run* and cmd.retcode. cmd.run_all no longer is the only one of these
that logs the cmd output at loglevel ERROR if the retcode is nonzero.
If the command has a nonzero exit status, then the minimum loglevel at
which the output will be logged is ERROR (if the output_loglevel was set
higher, than that level will be used).

The "quiet" loglevel still works as before, suppressing all output
logging for the command, even if there was an error.
Fix refs to cmd.run* with quiet=True

This changes these references to use output_loglevel='quiet'
Lower loglevel for verbose pkg mgmt commands

This uses the new output_loglevel argument to force these commands to
log their output to loglevel DEBUG. Note that any error encountered in
running these commands will log the output at loglevel ERROR.
Add 'critical' loglevel to salt.log.setup.LOG_LEVELS
Fix spelling error
Force prereq to be formed as a list
lint fixes for mysql tests
Make the change on *both* verify_high calls
Merge pull request #9221 from basepi/prereqerror8235

Error out if prereq is not formed as a list, Fix #8235
remove reduntant faulty test
Laying the groundwork for overstate unit testing.
Pylint
pylint fixes
Pass the psudo funcs into the renderer
Fixed a typo in the title of the digital ocean docs.
Expose the highstate while we're building it, to let pydsl include correctly.
Unit test for including a state multiple times using pydsl.
Missing newline