Do not let Crypt_Blowfish die on exceptions.

Do not let Crypt_Blowfish die on exceptions.

I'm not 100% certain this commit introduces the best way of dealing
with Crypt_Blowfish errors. As far as I can see there are four
situations that Crypt_Blowfish considers to be an error. In each of
these cases the library will unconditionally raise a PEAR error with
the mode "PEAR_ERROR_DIE". Which will unconditionally kill us.

Apparently one such situation has already been hit (commit
271ce27ceee4749c667b3d0b51be8947c915472d).

Now we are double checking input in both Horde_Secret and
Crypt_Blowfish but on the other hand we don't have to check the return
values anymore.