Fix potential double close() on exception
Fix potential double close() on exception

Summary:
Fix potential double close() on exception when SO_REUSEPORT fails.
The fd will be closed twice, once by close() and second by the scope guard above.

Reviewed By: yfeldblum

Differential Revision: D4272300

fbshipit-source-id: a163be822d7522cadb9dc3c3eddca10df453de14

floxard/folly,charsyam/folly,charsyam/folly,rklabs/folly,Orvid/folly,floxard/folly,rklabs/folly,facebook/folly,floxard/folly,facebook/folly,rklabs/folly,Orvid/folly,Orvid/folly,facebook/folly,Orvid/folly,charsyam/folly,facebook/folly,floxard/folly,rklabs/folly,facebook/folly,charsyam/folly,Orvid/folly,floxard/folly,rklabs/folly