Bug 8166 - Adding new currencies & exchange rates

Bug 8166 - Adding new currencies & exchange rates

if not fill any field it save blank record

To Test:
1) Go to Currencies & Exchange rates.
2) Create New currency
3) If you not fill any field for ex: (Currency, rate, symbol)
   it will not save the record.

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
(cherry picked from commit 42dbe025d953ef9809a1330be4517e393d49ea4a)

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>