In 2014, the update of the diagnostics recipes from 1.8.3 to 1.8.4
failed due to reasons that seem not to be relevant anymore in the
current version 1.8.10. As the diagnostic-aggregator recipe failed
with gcc6 (cf. https://github.com/bmwcarit/meta-ros/issues/392

),
I revisited the diagnostics recipes and this commit updates them.
The current diagnostics recipes in version 1.8.10 do not fail with
gcc6, and is one step forward to build meta-ros with gcc6.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>