[Rd] avas: segmentation fault on empty args (PR#2352)

[vograno@arbitrade.com]

Full_Name: Vadim Ogranovich
Version: 1.6.0
OS: Red Hat 7.1
Submission from: (NULL) (209.99.241.1)


Segmentation fault occurs when empty vectors passed to avas as arguments. 

> library("acepack")
library("acepack")
> avas(numeric(0),numeric(0))
avas(numeric(0),numeric(0))

Process R segmentation fault at Fri Dec  6 10:31:06 2002