vsftpd: update to replace old setrlimit call

[miken32]

Description

Closes: https://trac.macports.org/ticket/67134

I don't know if this will break macOS versions prior to Monterey. Currently Monterey and later are broken, which seems like a worse state to be in. Likely someone with more knowledge of the build environment could target the patch better.

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 14.6.1 23G93 arm64
Xcode 16.2 16C5032a

Verification

Have you

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• [ x] referenced existing tickets on Trac with full URL in commit message?
• [x ] checked your Portfile with port lint?
• [x ] tried existing tests with sudo port test?
• [x ] tried a full install with sudo port -vst install?