Fix another two instances of dead code in MythNetVision. Coverity 703656,703657
Fix null pointer dereference in MythNetVision's NetSearch. Coverity 1026719, 703773
Fix uninitialised member pointer warning in MNV NetSearch. It was unused so I removed it. Coverity 1026733
Fix uninitialised member pointer in MNV NetTree. Coverity 1026734
Fix null pointer dereference in MNV NetTree. Coverity 1026722