Bug#653378: Please build-depend on firebird-dev
qt-x11 is currently build-depending on firebird2.5-dev. As of version
184.108.40.206349-0~rc1.ds4-3 the package is renamed to firebird-dev and
firebird2.5-dev is a transitional package, which I want to drop when all
packages build-depending on it are changed to build-depend on firebird-dev
This is supposed to be the last rename of the firebird development package. The
API is supposed to always be backwards compatible (which was the case for the
last 10 years).