Validate that Julia is using our pre-installed conda

tests/julia/pyplot/verify

@@ -1,6 +1,12 @@
 #!/usr/bin/env julia
-# We try to plot something, and see if the file saved exists
 using PyPlot
+
+# Make sure we are re-using the same conda python
+if PyCall.python != "/srv/conda/bin/python"
+    exit(1)
+end
+
+# We try to plot something, and see if the file saved exists
 x = linspace(0,2*pi,1000); y = sin(3*x + 4*cos(2*x))
 plot(x, y, color="red", linewidth=2.0, linestyle="--")
 savefig("graph.png")