match args ignored in enumerate devices

[guruofquality]

If the match args specify any unique keys like serial or device addresses, they should not yield results when those values do not match the ones in the discovery for loop. This is necessary to select a specific device either by manually specifying an identifying key/value like serial or using the exact results from the enumeration

There also seems to be a bug where the serial number is empty

• reference issue: If more than one SDR device is connected to a Host system then only the first detected SDR device is opened pothosware/SoapySDR#248
• see findIConnection(const SoapySDR::Kwargs &matchArgs)

[curtcorum]

@jhshark

In progress on preliminary fix for enumeration match, at least for the 'device' keyword. Will do a pull request at some point.