util: pidfile: Sanitize return values of virPidFileReadIfAlive
util: pidfile: Sanitize return values of virPidFileReadIfAlive

Return -1 on failure rather than -errno since none of the callers
actually cares about the return value. This specifically fixes returns
of -ENOMEM in cases of bad usage, which would report wrong error
anyways.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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