.travis.yml: Removed ancient GCC toolchain 4.9, 5, and 6 from the build matrix...
.travis.yml: Removed ancient GCC toolchain 4.9, 5, and 6 from the build matrix...

oktal/rest,oktal/pistache,oktal/rest,oktal/pistache,oktal/rest,oktal/pistache,oktal/pistache,oktal/rest,oktal/pistache