perf session: Don't call dump_sample() when evsel is NULL
perf session: Don't call dump_sample() when evsel is NULL

Need to check evsel before passing it to dump_sample().

Signed-off-by: Kan Liang <6e4ed0645dbf05e706dc43d69b381839dca8944b@intel.com>
Cc: Adrian Hunter <41bb5944f244750b7cf0394140496972a3f1bee3@intel.com>
Cc: Andi Kleen <0474aee45985f5ae829f53849df476200e876990@linux.intel.com>
Cc: Andy Lutomirski <2cc0d0d76de2e6f37b92deeb83c85cb306fc5dc1@kernel.org>
Cc: Jiri Olsa <2c6594f608aa3d41e98d48846a6328831f7084ad@kernel.org>
Cc: Mark Rutland <1db9dd262beaa64f35756dd39531d9747b7778bb@arm.com>
Cc: Namhyung Kim <5c915a589b3ddf58cebf14bec41bcc143b37ac3c@kernel.org>
Cc: Peter Zijlstra <645ca7d3a8d3d4f60557176cd361ea8351edc32b@chello.nl>
Cc: Stephane Eranian <f199ae9781930a5b94b284ca2f471140752002a7@google.com>
Link: http://lkml.kernel.org/r/1441283463-51050-5-git-send-email-6e4ed0645dbf05e706dc43d69b381839dca8944b@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <293abb6b76d7791c0732cc517d38c4b5c734b87f@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs