Per [(1), i.e. test(1), the string comparison operator should be `=`,
not `==` in sh(1) scripts.
No functional change. FreeBSD's test accepts `==` as an alias for `=`
for compatibility with gnu test's `==` extension.
Reviewed by: imp@, gjb@
Pull Request: https://github.com/freebsd/freebsd-src/pull/485
3f197b101f