Fix TestNUTSLKJCholeskyCov (#2997)

* Fix TestNUTSLKJCholeskyCov

* More explicit args

Author: ColCarroll

pymc3/tests/sampler_fixtures.py

@@ -110,7 +110,7 @@ def make_model(cls):
         with pm.Model() as model:
             sd_mu = np.array([1, 2, 3, 4, 5])
             sd_dist = pm.Lognormal.dist(mu=sd_mu, sd=sd_mu / 10., shape=5)
-            chol_packed = pm.LKJCholeskyCov('chol_packed', 5, 3, sd_dist)
+            chol_packed = pm.LKJCholeskyCov('chol_packed', eta=3, n=5, sd_dist=sd_dist)
             chol = pm.expand_packed_triangular(5, chol_packed, lower=True)
             cov = tt.dot(chol, chol.T)
             stds = tt.sqrt(tt.diag(cov))