Single-quote character in text fields may be pushed incorrectly

[VMikhailovskii]

Looks like this happens due to
https://github.com/CiscoDevNet/python-viptela/blob/master/vmanage/api/http_methods.py#L65
where we replace single-quote with double-quote.

However the string may be defined with both single- and double-quotes... means the replace does following

from
"test ' single quote"
it convers to
"test " single quote"
that is obviously incorrect string format.