Bug 27869: let user know something went wrong with csv upload

Bug 27869: let user know something went wrong with csv upload

To test:
-attempt to upload a malformed CSV file
-nothing happens, check the console and see the error: Uncaught TypeError: arrData[(arrData.length - 1)] is undefined
-apply patch
-try again
-now you should at least see a warning that something went wrong
-attempt to upload a good CSV file, it should work

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Joonas Kylmälä <joonas.kylmala@helsinki.fi>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>