img: Switching to syslinux 6.03
img: Switching to syslinux 6.03

6.03 is now released, let's use it

enovance/edeploy,enovance/edeploy,lebauce/edeploy,redhat-cip/edeploy,redhat-cip/edeploy,redhat-cip/edeploy,lebauce/edeploy,redhat-cip/edeploy,lebauce/edeploy,enovance/edeploy,enovance/edeploy,lebauce/edeploy