Allow passing NULL regexps in some regexp routines
Allow passing NULL regexps in some regexp routines

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