www/apache24: Update to 2.4.51

Fixes: critical: Path Traversal and Remote Code Execution in Apache
HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)
(CVE-2021-42013)

PR: 258988
MFH: 2021Q4
Security: CVE-2021-41773, CVE-2021-42013