Noticed from Lintian messages.  Most of the wrappers associated with
xen-utils should be in /usr/libexec, not /usr/lib (PyGRUB also has this
issue, as you're not likely to run it as a command very often).

I'm also including a patch which should be valuable as a first phase
*now*.  The issue is future versions of xen-utils-common will need to
remain compatible with older versions of xen-utils-X.Y.  As such current
versions of xen-utils-* should start including compatibility symlinks.

This still seems a Good Idea(tm) to start the process of moving to
/usr/libexec, but I do update patches if I discover issues.

Note, for the shorter term it makes sense to leave things in /usr/lib.
Until a few revisions pass with both /usr/lib and /usr/libexec copies,
xen-utils-common must keep using /usr/lib.  Issue is once
xen-utils-common uses /usr/libexec, older installations break.  Best to
keep compatibility with old builds for a while.