perf inject: Make --strip keep evsels

create_gcov (refer to the autofdo example in tools/perf/Documentation/intel-pt.txt)
now needs the evsels to read the perf.data file. So don't strip them.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20191105100057.21465-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>