perf trace: Fix error reporting for evsel pgfault constructor

perf trace: Fix error reporting for evsel pgfault constructor

In that case the only failure possible is not to have enough memory, as
we are just creating the evsels, not trying to access any system
facility such as debugfs files or syscalls.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.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-7k6asvfhiwiu2zs6o2oknchk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>