Update vocabulary-embedding.ipynb

[ashishrana160796]

With the following code :
!unzip {datadir}/{path} while executing is producing the following error.
unzip: cannot find or open /home/user_name/.keras/datasets//home/user_name/.keras/datasets/glove.6B.zip, /home/user_name/.keras/datasets//home/user_name/.keras/datasets/glove.6B.zip.zip or /home/user_name/.keras/datasets//home/user_name/.keras/datasets/glove.6B.zip.ZIP.

Removing {datadir} removes the above error and files are extracted successfully.

[udibr]

Looks like something wrong with Keras. According to their manual
the get_file(path, ... command should have placed the file at {datadir}/{path}

[ashishrana160796]

I think keras's get_file method works fine as it returns the path variable pointing to given directory's file /home/user_name/.keras/datasets/glove.6B.zip which is consistent with documentation and also file is placed there after execution( pardon me, didn't mentioned it earlier). But, I think problem arises when {datadir} is appended to unzip leading to duplication as pointed out by above error message.
Please see if the similar issue is reproducible by you as I am using keras 2.1.5 or is there something wrong with my analysis.

-Thanks