Anaconda doesn't download the filelists or 'other' metadata, which can
add a significant amount of space to the metadata cache on the build
host. So to estimate the amount of space needed by Anaconda exclude the
space used by *filelists* and *other* files.
With these changes the lorax-composer estimate should actually be fairly
accurate. But since Anaconda only uses the installedsize * 1.35 we have
to make sure that the size we use is at least as big as what anaconda
will estimate, otherwise the installation will fail.
Resolves: rhbz#1761337