Use xorriso instead of genisoimage

xorriso make the image reproducible (given the same input files),
including support for SOURCE_DATE_EPOCH in various metadata.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

pungi.spec

@@ -40,7 +40,7 @@ Requires:       jigdo
 Requires:       cvs
 Requires:       yum-utils
 Requires:       isomd5sum
-Requires:       genisoimage
+Requires:       xorriso
 Requires:       gettext
 Requires:       syslinux
 Requires:       git

pungi/gather.py

@@ -1740,7 +1740,7 @@ class Pungi(PungiBase):
                            clean=True) # This is risky...
 
         # setup the base command
-        mkisofs = ['/usr/bin/mkisofs']
+        mkisofs = ['/usr/bin/xorriso', '-as', 'mkisofs']
         mkisofs.extend(['-v', '-U', '-J', '--joliet-long', '-R', '-T', '-m', 'repoview', '-m', 'boot.iso']) # common mkisofs flags
 
         x86bootargs = ['-b', 'isolinux/isolinux.bin', '-c', 'isolinux/boot.cat',