apt: Use --no-install-recommends to avoid unnecessary extras

[jnohlgard]

Add --no-install-recommends to apt-get commands to avoid pulling in optional dependencies which are not used by the build process.

The image size reduction is approximately 430 MB

REPOSITORY                 TAG                 IMAGE ID            CREATED             SIZE
riot/riotbuild             norecommends        402547be3514        3 minutes ago       3.34 GB
riot/riotbuild             master              e4c568fc283a        44 minutes ago      3.77 GB

Testing

This needs a full buildtest run on the new image to ensure that no critical components are missing after adding this flag, but my laptop does not have the disk space or time to do it.

[cladmi]

I will run the buildtest during the release with this version.

[jnohlgard]

Thanks, @cladmi!

[cladmi]

I ran the compilation test with this, scan-build in one example, and also the static-test.

I will merge after the release.

[cladmi]

Only failed build was tests/gnrc_ipv6_nib but it also fails with the current image.

BOARD=waspmote-pro make -C tests/gnrc_ipv6_nib

RIOT-OS/Release-Specs#76 (comment)

[cladmi]

I ACK but just wait for the release cycle to be finished for merging.

[jnohlgard]

Thanks, @cladmi!

[cladmi]

@smlng @kaspar030 do you see any other checks that should be done ? like for using it in murdock or something I missed

[cladmi]

ACK. There were no objections said on this one.
Please rebase and merge when travis is happy.

[jnohlgard]

Rebased