Skip network adapters that are disconnected

[ZLJasonG]

Don't fail to initialise if a network adapter is disconnected.

fixes #326

[ZLJasonG]

#326

[coveralls]

Coverage decreased (-0.1%) to 93.642% when pulling 2727f45 on ZLJasonG:patch-1 into 5e268fa on jstasiak:master.

[jstasiak]

Thank you! Two small comments, looks good otherwise.

[bdraco]

@ZLJasonG would you please rebase this PR to the latest master?

[bdraco]

fixes #326

[codecov-commenter]

Codecov Report

Merging #327 (877559c) into master (662ed61) will decrease coverage by 0.03%.
The diff coverage is n/a.

❗ Current head 877559c differs from pull request most recent head fe65d5b. Consider uploading reports for the commit fe65d5b to get more accurate results

@@            Coverage Diff             @@
##           master     #327      +/-   ##
==========================================
- Coverage   98.72%   98.68%   -0.04%     
==========================================
  Files          22       22              
  Lines        2271     2279       +8     
  Branches      389      389              
==========================================
+ Hits         2242     2249       +7     
  Misses         18       18              
- Partials       11       12       +1     

Impacted Files	Coverage Δ
zeroconf/_utils/aio.py	96.00% <0.00%> (-2.00%)	⬇️
zeroconf/_dns.py	100.00% <0.00%> (ø)

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[bdraco]

Looks like WSAENOPROTOOPT is mapped to ENOPROTOOPT

https://github.com/python/cpython/blob/main/Modules/errnomodule.c#L253