fix NameValueList equals, in case this is an empty NameValueList

[macvoo]

Calling NameListValue#equals on a empty NameValueList (handing over another NameValueList) would always return true in the current implementation.

CodeSample:
//Given:
NameValueList a = new NameValueList();
NameValueList b = new NameValueList();
b.set("someName", "someValue");
//When
a.equals(b); --> would be true, but should be false...

[gsaslis]

Hey @macvoo !

Thanks for taking the time to submit this PR ❤️ !!

Could you please take a look at our Open Source Playbook and then proceed with signing our CLA, so we can then move forward with processing this?

Thanks in advance!
Yorgos

[gsaslis]

thanks for signing the CLA @macvoo !

Passing this on for review.