Errors building docker images.

[BorjaOuterelo]

Hi, I found errors building the docker images:

• bootstrap cannot be found.
  RUN cd tools/kconfig-frontends && ./bootstrap && ./configure && make
• Build hands running the line:
  RUN cd buildroot && /root/script.exp

Those errors are:

• bootstrap is not part of kconfig-frontends anymore since version 4.11.0.1. Nuttx tools updated on commit: Nuttx update
• GCC version changed to 7.3.0 So the expect script hands on trying to match
  9. gcc 7.2.0 (BR2_GCC_VERSION_7_2_0) (NEW)\r

Solution proposed: pull

Questions:

• Shall we agree a Nuttx tools version to go avoiding same errors in the future? I see that we use also use Nuttx buildroot. Shall this be fixed aswell?