scripts: deal with shell incompatibilities

In dash echo is a builtin that does not support -e as a result we did
generate broken header files on Ubuntu and newer Debian systems.
For make_relaese just enforce bash as the shell of our choice.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>