src: Align make output
    
    The make inserts six spaces instead of four:
    
      GEN      access/viraccessapichecklxc.h
      GEN    hyperv/hyperv_wmi.generated.h
      GEN      access/viraccessapichecklxc.c
      GEN    hyperv/hyperv_wmi.generated.c
      GEN    hyperv/hyperv_wmi_classes.generated.typedef
      GEN    hyperv/hyperv_wmi_classes.generated.h
      GEN    hyperv/hyperv_wmi_classes.generated.c
      GEN      libvirt_access_qemu.xml
      GEN      libvirt_access.syms
      GEN      libvirt_access_lxc.xml
      GEN      libvirt_access_qemu.syms
      GEN      libvirt_access_lxc.syms
      GEN      libvirt_qemu.def
      GEN    esx/esx_vi_types.generated.typedef
      GEN    esx/esx_vi_types.generated.typeenum
      GEN    esx/esx_vi_types.generated.typetostring
      GEN    esx/esx_vi_types.generated.typefromstring
      GEN    esx/esx_vi_types.generated.h
      GEN    esx/esx_vi_types.generated.c
      GEN    esx/esx_vi_methods.generated.h
      GEN    esx/esx_vi_methods.generated.c
      GEN    esx/esx_vi_methods.generated.macro
      GEN    esx/esx_vi.generated.h
      GEN    esx/esx_vi.generated.c
      GEN      libvirt_lxc.def
    
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>