cpu.c: Check properly for virCapabilitiesGetNodeInfo() retval
cpu.c: Check properly for virCapabilitiesGetNodeInfo() retval

The virCapabilitiesGetNodeInfo() function has the usual return
value semantics for integeres: a negative value means an error,
zero or a positive value means success. However, the function
call done in virCPUProbeHost() doesn't check for the return value
accordingly.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>

libvirt/libvirt,jardasgit/libvirt,crobinso/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,zippy2/libvirt,nertpinx/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,olafhering/libvirt,crobinso/libvirt,nertpinx/libvirt,zippy2/libvirt,olafhering/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,libvirt/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,zippy2/libvirt,libvirt/libvirt,nertpinx/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,jfehlig/libvirt,olafhering/libvirt,crobinso/libvirt,olafhering/libvirt,zippy2/libvirt,nertpinx/libvirt