[BUG] 0.19 cudf empty df assignment issues

[jperez999]

Describe the bug
Cannot perform previously available functionality against empty dataframe.

Steps/Code to reproduce bug
!!!Cudf branch 0.19!!!

import cudf
jdf = cudf.DataFrame({"alpha": [1,2,3,3,4,5,6]})
gdf = cudf.DataFrame()
new_cols = [c for c in jdf.columns if c not in gdf.columns]
gdf[new_cols] = jdf[new_cols]
print(gdf)

result:

Empty DataFrame
Columns: [alpha]
Index: []

Expected behavior
Expect dataframe gdf to have the column names and values of the jdf dataframe new_cols columns. This change occurred about a week ago.