debian/control: recommend xzdec

Fix "Can't exec "xzdec": No such file or directory at
build/Build/Arch.pm line 153." by adding xzdec recommend.

Signed-off-by: Héctor Orón Martínez <zumbi@debian.org>

debian/control

@@ -12,7 +12,7 @@ Package: obs-build
 Architecture: all
 Depends:
  ${misc:Depends}, ${perl:Depends}, rpm, debootstrap, sudo, libarchive-tools
-Recommends: rpm2cpio, osc, libcrypt-ssleay-perl
+Recommends: rpm2cpio, osc, libcrypt-ssleay-perl, xzdec
 Description: scripts for building RPM/debian packages for multiple distributions
  This package provides scripts for building RPM and debian packages in
  contained environments for various build distributions. These tools