Don't die on NULL entries in args
Don't die on NULL entries in args

There is no guarantee that parseline will fill all of args with strings,
empty or otherwise; chk_args needs to be prepared that any entry in args
can be NULL.

Also, parseline initializes all args as NULL now to guard against garbage
pointers accumulating from previous uses.

hercules-team/augeas-do-not-use,mchf/augeas,manandbytes/augeas,mlichvar/augeas,jjlin/augeas,mchf/augeas,camptocamp/augeas,GeoffWilliams/augeas,dafugg/augeas,lutter/augeas,kumy/augeas,bkearney/augeas,jjlin/augeas,hercules-team/augeas,pevalme/augeas,camptocamp/augeas,jtopjian/augeas,hercules-team/augeas,pevalme/augeas,ptoscano/augeas,domcleal/augeas,jasperla/augeas,manandbytes/augeas,GeoffWilliams/augeas,lutter/augeas,domcleal/augeas,kunkku/augeas,kunkku/augeas,mlichvar/augeas,bkearney/augeas,camptocamp/augeas,bkearney/augeas,camptocamp/augeas,raphink/augeas,jtopjian/augeas,jjlin/augeas,kumy/augeas,ptoscano/augeas,ptoscano/augeas,dafugg/augeas,bkearney/augeas,MikaelSmith/augeas,lutter/augeas,raphink/augeas,jasperla/augeas,hercules-team/augeas-do-not-use,kumy/augeas,hercules-team/augeas-do-not-use,mlichvar/augeas,dafugg/augeas,domcleal/augeas,kunkku/augeas,kumy/augeas,pevalme/augeas,MikaelSmith/augeas