devel/libee: Fix missing distfile, level up port compliance

Upstreams MASTER_SITES changed, and was no longer serving libee's distfile,
but a redirect instead:

=> Fetched file size mismatch (expected 357116, actual 19835)

Rainer (rsyslog maintainer) graciously made it available again on my
request via Twitter.

While I'm here:

• pet portlint: WARN: Makefile: "USES" has to appear earlier.
• Fix LICENSE (license text body reads LGPL21+)
• --prefix is already set by framework, remove from CONFIGURE_ARGS

Approved by: portmgr (framework compliance)
MFH: 2019Q2