fix version script to include header and not write file twice
fix version script to include header and not write file twice

bw-oss/iw,OSLL/iw,chunyeow/iw,TeamEOS/external_iw,cozybit/iw,bcopeland/android_iw,Distrotech/iw,greearb/iw-ct,CTU-IIG/802.11p-iw,bw-oss/iw,Distrotech/iw,SoluMachines/external_iw,OSLL/iw,TeamEOS/external_iw,chunyeow/iw,timduru/platform-external-iw,ewa/iw-modified,SoluMachines/external_iw,idor/iw,greearb/iw-ct,cozybit/iw,ewa/iw-modified,CTU-IIG/802.11p-iw,idor/iw,timduru/platform-external-iw,bcopeland/android_iw