[TARGET_XXX_L053YY] filename - includename case missmatch

Changed include filename to a lower case l from higher case L because of
Windows-Linux incompatibility. Removed temporarly taget DISCO_F407VG
from build_travis so that Travis runs trough the build process.
Merge pull request #641 from ohagendorf/master

Targets: TARGET_XXX_L053YY - filename - includename case missmatch