We don't always have the tools tree available yet when generating the
cache manifest which can lead to cache manifest mismatches depending on
whether the tools tree is available or not. Since the package manager field
depends on whether the tools tree is available or not (dnf or dnf5, dnf or zypper),
let's remove it from the cache manifest.
"release": self.release,
"mirror": self.mirror,
"architecture": self.architecture,
- "package_manager": self.distribution.package_manager(self).executable(self),
"packages": sorted(self.packages),
"build_packages": sorted(self.build_packages),
"package_directories": [