perf probe: Fix to return 0 when positive value returned
perf probe: Fix to return 0 when positive value returned

Fix to return 0 when positive value returned from probe command.

At least --vars can returns a positive value if it found a point.
  ----
  # perf probe --vars vfs_read && echo succeeded! || echo failed!
  Available variables at vfs_read
          @<vfs_read+0>
                  char*   buf
                  loff_t* pos
                  size_t  count
                  struct file*    file
  failed!
  ----

This fixes above problem.
  ----
  # perf probe --vars vfs_read && echo succeeded! || echo failed!
  Available variables at vfs_read
          @<vfs_read+0>
                  char*   buf
                  loff_t* pos
                  size_t  count
                  struct file*    file
  succeeded!
  ----

Signed-off-by: Masami Hiramatsu <60fcdccfd958d359debfe6e6e7417cd7f1aaa9e3@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <293abb6b76d7791c0732cc517d38c4b5c734b87f@redhat.com>
Cc: Ananth N Mavinakayanahalli <7dc108d19a2513f6455353af182b9e4d3b794ec9@in.ibm.com>
Cc: David Ahern <b80c1600f604d3b0d768f26f90a76757e76005dd@gmail.com>
Cc: Hemant Kumar <7123f6a6628a9fc84f20db1d8af7bbec27c94c78@linux.vnet.ibm.com>
Cc: Jiri Olsa <2c6594f608aa3d41e98d48846a6328831f7084ad@redhat.com>
Cc: Namhyung Kim <5c915a589b3ddf58cebf14bec41bcc143b37ac3c@kernel.org>
Cc: Peter Zijlstra <3fddac958924aef220f202ca567388ddab3f14a8@infradead.org>
Link: 10d987dff53a8865d0184300e981855494b0c41b@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <293abb6b76d7791c0732cc517d38c4b5c734b87f@redhat.com>

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