devel/py-fabric3: fix "fetch" stage for v1.14

• mark as no longer BROKEN;
• use .post1 as DISTVERSIONSUFFIX;
• change DISTNAME accordingly;
• while here, remove flavors from USE_PYTHON.

Reported by: pkg-fallout
Reviewed by: mat
Approved by: araujo (mentor)
Differential Revision: https://reviews.freebsd.org/D18480
Thanks to: antoine, mat, araujo