tools: Don't check the output of virGetUserCacheDirectory()
tools: Don't check the output of virGetUserCacheDirectory()

virGetUserCacheDirectory() *never* *ever* returns NULL, making the
checks for it completely unnecessary.

Signed-off-by: Fabiano Fidêncio <2931bae082ef9bc04523ba759c03a4778316d48f@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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