perl-crypt-blowfish: add missing license declaration

perl-crypt-blowfish: add missing license declaration

The license of this package is not standard, it is a combination of two
sets of statements coming from two different authors.

The license resembles the original 4-clause BSD license (thus including
advertising clause) but without the third clause about endorsement.
The label 'BSD-4-Clause-like' nevertheless seems the closest match.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>