perf tools: Improve libbfd detection message

Before:

  No bfd.h/libbfd found, install binutils-dev[el]/zlib-static to gain symbol demangling

After:

  No bfd.h/libbfd found, please install binutils-dev[el]/zlib-static/libiberty-dev to gain symbol demangling

Change the message to the standard 'please install' language and also
add libiberty-dev suggestion for Ubuntu systems.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <david.ahern@oracle.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150228084610.GE31887@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>