Fix socket descriptor leak in fastcgi_connect()

Found by Coverity-scan (CID 330051)

@Deuce should review this.
14 jobs for master in 11 minutes and 25 seconds (queued for 11 seconds)
Status Job ID Name Coverage
  Build
passed #18180
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jsdoor-freebsd

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passed #18181
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jsdoor-linux

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jsdoor-windows

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sbbs-freebsd

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sbbs-linux

00:09:58

passed #18173
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sbbs-windows

00:05:24

passed #18182
FreeBSD
sexpots-freebsd

00:00:13

passed #18171
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sexpots-linux

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Windows
sexpots-windows

00:00:26

passed #18178
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syncdraw-freebsd

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syncdraw-linux

00:01:25

passed #18176
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syncterm-freebsd

00:01:19

passed #18172
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syncterm-linux

00:03:13

passed #18177
FreeBSD
syncterm-windows

00:02:18