resolve build error 'invalid from flag value 0: repository sha256 not found: does not exist or no pull access'
Signed-off-by: Brett Johnson <brett@sdbrett.com>
Make necessary change to make things work with photon 2.0 docker image.
Remove distro-sync to mitigate the build issue and add `--pull` to docker build
command to make sure the latest photon:2.0 will be pulled during build process.
Signed-off-by: Daniel Jiang <jiangd@vmware.com>