closes #1801 closes #1803
uses now __class__ attribute to find the distribution class instead of accessing through module
TravisCI has no scipy 0.14 that would test this
TST error with scipy 0.14 location distribution class, closes #1801 c…
Coverage remained the same when pulling 4a9650d on josef-pkt:bug_scipy_distribution_1801 into 311552e on statsmodels:master.