Make --tlsverify enable tls regardless of value specified

I also needed to add a mflag.IsSet() function that allows you to check
to see if a certain flag was actually specified on the cmd line.

Per #9221 - also tweaked the docs to fix a typo.

Closes #9221

Signed-off-by: Doug Davis <dug@us.ibm.com>
Merge pull request #9259 from duglin/Issue9221

Make --tlsverify enable tls regardless of value specified