poisson_rnd is broken in 2.1.58

[Michael Creel]

Hello, 
The poisson_rnd function should return a matrix of the same size as the input, 
when one argument is passed. This worked in 2.1.57. I could probably make a 
patch, but perhaps someone who knows the origin of the bug would prefer to do 
that?

Michael


octave:2> poisson_rnd(ones(10,2))
error: operator -: nonconformant arguments (op1 is 15x1, op2 is 1x15)
error: evaluating binary operator `-' near line 104, column 23
error: evaluating assignment expression near line 103, column 20
error: evaluating if command near line 102, column 2
error: evaluating while command near line 100, column 7
error: evaluating if command near line 96, column 5
error: evaluating if command near line 67, column 3
error: called from `poisson_rnd' in file 
`/home/mcreel/octave/share/octave/2.1.58/m/statistics/distributions/poisson_rnd.m'
octave:2>