Replace "-devel" occurences with "-dev"

Some "-devel" extensions could be found in generated recipes. Yocto
uses  "-dev" extensions instead of "-devel". This patch attempts to
replace the remainings "-devel" extensions.

Signed-off-by: Kévin THIERRY <kevin.thierry@open.eurogiciel.org>
Replace tabulations with spaces in spec2yocto.py

Signed-off-by: Kévin THIERRY <kevin.thierry@open.eurogiciel.org>