fix reading variable names in mfiles with a subsystem entry

Author: jebej

src/MAT_HDF5.jl

@@ -275,7 +275,7 @@ Return a list of variables in an opened Matlab file.
 
 See `matopen`.
 """
-names(f::MatlabHDF5File) = filter!(x->x != "#refs#", names(f.plain))
+names(f::MatlabHDF5File) = filter!(x -> x!="#refs#" && x!="#subsystem#", names(f.plain))
 
 """
     exists(matfile_handle, varname) -> Bool

test/read.jl

@@ -217,7 +217,7 @@ end
 # since we don't support these objects, just make sure that there are no errors
 # reading the file and that the variables are there and replaced with `missing`
 let objtestfile = "struct_table_datetime.mat"
-    vars = matopen(m->read(m,"s"), joinpath(dirname(@__FILE__), "v7.3", objtestfile))
+    vars = matread(joinpath(dirname(@__FILE__), "v7.3", objtestfile))["s"]
     @test "testTable" in keys(vars)
     @test ismissing(vars["testTable"])
     @test "testDatetime" in keys(vars)