Update mbdata to the lucifer version v27.0.dev2

It is almost the same version as before, just with restored tests and
unambiguous version (which was otherwise detected as v26.something).

Author: yvanzo

requirements.txt

@@ -1,7 +1,7 @@
 amqp==2.5.2
 backports.functools_lru_cache==1.0.1
 enum34==1.1.6
-git+https://github.com/amCap1712/mbdata.git@bc3fc985c9842396ac7a0a1190072c093213afeb#egg=mbdata
+git+https://github.com/amCap1712/mbdata.git@v27.0.dev2#egg=mbdata
 git+https://github.com/metabrainz/[email protected]#egg=mb-rngpy
 psycopg2==2.8.4
 retrying==1.3.3