Fix not following RFC6763 section 6.3

[mgirard1mtx]

RFC6763 section 6.3:
Specifies that each key/value pair is encoded as its own constituent string. So each bytes length + string is a key value pair.

I tested this with an IPMX registry device.

Before the fix the Attribute where mangled (a single key/pair).

After the proposed fix each Key Value pairs matches the output from standard tools like dig.

[mgirard1mtx]

Here is an example dig answer to a TXT request:

;; ANSWER SECTION:
deviceNameRemoved._nmos-register._tcp.matrox.com. 0 IN TXT "api_ver=v1.0,v1.1,v1.2,v1.3" "api_proto=http" "pri=5" "api_auth=false"

In this case the TXT RData contains 4 strings which are each key value pairs:

• "api_ver=v1.0,v1.1,v1.2,v1.3"
• "api_proto=http"
• "pri=5"
• "api_auth=false"

[mgirard1mtx]

@kapetan do I need to do something for that p.r. ?

The txt have a slight bug where multi Txt record are not handle properly (we treat the list of key value as a single key value pair).

[Neustradamus]

@kapetan: Have you seen this PR?