perf tools: Fix installation of libexec components

perf tools: Fix installation of libexec components

Doing a fresh install on a user home directory needs to first make sure
that the ~/libexec/perf-core/ directory is present so that
'perf-archive' like scripts, 'perf test' attr config files and 'perf
script' scripts can be installed.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-z7ryi3r1b9dn9smbfnab0fdc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>