Update Julia tests for new conda env path

tests/julia/julia_version-1.0.2/verify

@@ -17,7 +17,7 @@ end
 # Verify that kernels are not installed in home directory (issue #620)
 try
     using IJulia
-    @assert IJulia.kerneldir() == "/srv/conda/share/jupyter/kernels"
+    @assert IJulia.kerneldir() == ENV["NB_PYTHON_PREFIX"] * "/share/jupyter/kernels"
 catch
     exit(1)
 end

tests/julia/julia_version-default/verify

@@ -17,7 +17,7 @@ end
 # Verify that kernels are not installed in home directory (issue #620)
 try
     using IJulia
-    @assert IJulia.kerneldir() == "/srv/conda/share/jupyter/kernels"
+    @assert IJulia.kerneldir() == ENV["NB_PYTHON_PREFIX"] * "/share/jupyter/kernels"
 catch
     exit(1)
 end