Just a clarification.
Only the 'if', removing the 'empty value check' for updateContext will be put back.
The reason is that the mongo backend does a better job that the parser on the error message that is sent back.
Mongo backend has more info.

Everything else ( "not is use" ) stays the way it is in this PR.

Also, instead of that 'fixme' comment, we need a new comment saying something like:

       // For ngsi10 updateContextRequest, he check of empty context attribute values is made by
the mongoBackend layer, thus