perf machine: Fix up vdso methods names

perf machine: Fix up vdso methods names

To make it consistent with the other dso lifetime routines.

For instance:

 struct dso *vdso__new(struct machine *machine, const char *short_name,
		        const char *long_name)

Becomes:

 struct dso *machine__addnew_vdso(struct machine *machine, const
				  char *short_name, const char *long_name)

Because:

1) There is no 'struct vdso' for us to have vdso__ prefixed routines.

2) Because it will not really just create a new instance of 'struct
   dso', it'll call dso__new() but it will also insert it into the
   DSO's list/rbtree, and we have a method name for that: 'addnew',
   just like we have dsos__addnew().

3) So it is really a 'struct machine' operation, it is the first
   argument, etc.

This way the place where this is used gets consistent:

                if (vdso) {
                        pgoff = 0;
-                       dso = vdso__dso_findnew(machine, thread);
+                       dso = machine__findnew_vdso(machine, thread);
                } else
                        dso = machine__findnew_dso(machine, filename);

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/n/tip-r3w3tvh8exm9xfz3p4tz9qbz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>