cmo/addatt/volume seg fault for prisms

[millerta]

lagrit can not read a prism mesh that has has volume attribute added by cmo/addatt/volume

Add warning or do not allow or fix.

read avs stack.inp mo
cmo/addatt/mo/layertyp/VINT/scalar/nnodes/linear/permanent/gxaf/0.0
cmo/addatt/mo/volume/VDOUBLE/scalar/nelements/linear/permanent/gxaf/0.0
ADDATT/volume: creating new attribute: VDOUBLE

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x5557767b97e1 in ???
#1  0x5557767b8de5 in ???
#2  0x7fca48bf208f in ???
	at /build/glibc-wuryBv/glibc-2.31/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
#3  0x55577629ee4d in ???
#4  0x555775d52749 in ???
#5  0x555775cc8dcb in ???
#6  0x555775cc7bac in ???
#7  0x555775cc4938 in ???
#8  0x555775cc4982 in ???
#9  0x7fca48bd3082 in __libc_start_main
	at ../csu/libc-start.c:308
#10  0x555775cc430d in ???
#11  0xffffffffffffffff in ???
Segmentation fault (core dumped)