CID 1047284 Uninitialized scalar variable (UNINIT)
CID 1047285 Uninitialized scalar variable (UNINIT)
CID 1047286 Uninitialized scalar variable (UNINIT)
If a performance variable session has no handles we should be returning MPI_SUCCESS
for MPI_T_pvar_start, MPI_T_pvar_stop, and MPI_T_pvar_reset. The code was returning
an unitialized value. This commit also updates the error code to return the proper
error on failure.
Signed-off-by: Nathan Hjelm <hjelmn@me.com>