So that we can erase the progress bar after we're done with it, avoiding
things like:

-------------------------------------------------------------------

          ┌─Error:──────────────────────────────────────────────────────┐
          │Can't annotate unmapped_area_topdown:                        │
          │                                                             │
          │No vmlinux file with build id a826726b5ddacfab1f0bade868f1a79│
          │was found in the path.                                       │
          │                                                             │
          │Note that annotation using /proc/kcore requires CAP_SYS_RAWIO│
┌Processin│                                                             │──┐
│         │Please use:                                                  │  │
└─────────│                                                             │──┘
          │  perf buildid-cache -vu vmlinux                             │
          │                                                             │
          │or:                                                          │
          │                                                             │
          │  --vmlinux vmlinux                                          │
          │                                                             │
          │                                                             │
          │Press any key...                                             │
          └─────────────────────────────────────────────────────────────┘

Can't annotate unmapped_area_topdown:
-------------------------------------------------------------------

I.e. that finished progress bar behind the error window. It is not a
problem when we end up redrawing the whole screen, but its ugly when
we present such error windows, provide a TUI method so that code like
the above may avoid this situation, as will be done with the annotation
code in the next cset.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-qvktnojzwwe37pweging058t@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>