Reading csv does not work

[dudzicp]

Describe the bug
ctx.read_csv( returns empty dataset

To Reproduce
`import datafusion

ctx = datafusion.SessionContext()

blasted = ctx.read_csv(path="/localpath/a.tsv", has_header=True, delimiter="\t", schema_infer_max_records=100)
blasted.show()
`
Expected behavior
Few rows from csv should be printed out

[dudzicp]

It turned out that file_extension argument is required:

df = ctx.read_csv(path="/localfile.tsv", has_header=True, delimiter="\t", file_extension="tsv")
loaded the dataframe properly.