Fix default commit author
Fix default commit author

Do not read any env variable, rely on Go to find it.

Fixes issue #55

jloehel/zypper-docker,mssola/zypper-docker,SUSE/zypper-docker,SUSE/zypper-docker,mssola/zypper-docker,jloehel/zypper-docker,mssola/zypper-docker,jloehel/zypper-docker,mssola/zypper-docker,SUSE/zypper-docker