mail/spamassassin: Update to 3.4.4

Update mail/spamassassin to 3.4.4. This fixes several security
vulnderabilities.

Changelog:

• Improvements to OLEVBMacro
• Fix for CRLF handling with SpamAssMilter & DKIM
• Small fix for a regexp to provide Perl 5.8.x compatability again
• Increased fns_extrachars default value to 50
• Fixed nosubject and maxhits tflags when sa-compile is used
• Limited the Bayes parsed token count
• Improvements to whitespace trimming

PR: 243744
Submitted by: cy
MFH: 2020Q1
Security: c86bfee3-4441-11ea-8be3-54e1ad3d6335