Fix mDNS socket leak during network configuration changes

Several rather important close() calls were embedded within
assert() macros.  Not a good idea, as the macros don't compile
into anything at all in non-debug builds, and the close() calls
disappear entirely.  This could eventually lead to failure of
the mDNS daemon when its file-descriptor table fills up with
orphans.

Bug: 13490553
Change-Id: I5978c055e8475d8f5be7e0242b80593b45ed71a1
3 files changed