Add python3-dev and python3-pip in former Dockerfile
Add python3-dev and python3-pip in former Dockerfile

Otherwise the former container cannot be built as Doctor requires a
full updated python3 env.

Change-Id: Ic90c13abad33e7cb15e7e51dcaac83b9ddf3930b
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

mywulin/functest,opnfv/functest,mywulin/functest,opnfv/functest