maint: fix typos related to disk name resolution
maint: fix typos related to disk name resolution

In a number of APIs, the text implied that a user might have
<target dev='xvda'/> - but common convention is to use "vda",
not "xvda".  For example, virDomainGetDiskErrors was correct,
while virDomainBlockStats was confusing.

* src/libvirt.c: Make examples consistent.

Signed-off-by: Eric Blake <a9da18479c871fe903d9590822cfe2629c6a4d11@redhat.com>

elmarco/libvirt,rlaager/libvirt,crobinso/libvirt,datto/libvirt,agx/libvirt,nertpinx/libvirt,eskultety/libvirt,datto/libvirt,jfehlig/libvirt,jfehlig/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,shugaoye/libvirt,nertpinx/libvirt,zippy2/libvirt,libvirt/libvirt,taget/libvirt,olafhering/libvirt,shugaoye/libvirt,jardasgit/libvirt,datto/libvirt,zippy2/libvirt,fabianfreyer/libvirt,taget/libvirt,andreabolognani/libvirt,elmarco/libvirt,olafhering/libvirt,shugaoye/libvirt,eskultety/libvirt,VenkatDatta/libvirt,olafhering/libvirt,shugaoye/libvirt,zippy2/libvirt,libvirt/libvirt,fabianfreyer/libvirt,olafhering/libvirt,shugaoye/libvirt,nertpinx/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,datto/libvirt,jfehlig/libvirt,eskultety/libvirt,jfehlig/libvirt,eskultety/libvirt,elmarco/libvirt,taget/libvirt,agx/libvirt,agx/libvirt,rlaager/libvirt,elmarco/libvirt,rlaager/libvirt,VenkatDatta/libvirt,crobinso/libvirt,jardasgit/libvirt,taget/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,elmarco/libvirt,datto/libvirt,jardasgit/libvirt,jardasgit/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,agx/libvirt,rlaager/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,libvirt/libvirt,andreabolognani/libvirt,libvirt/libvirt,agx/libvirt,rlaager/libvirt,zippy2/libvirt,taget/libvirt,crobinso/libvirt,crobinso/libvirt,eskultety/libvirt,nertpinx/libvirt