[conda] Completely remove "license_file" entry on conda recipe

See bob.devtools#44 and bob.devtools!127
4 jobs for fix_conda_license_file_issue in 17 minutes and 56 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #181230
docker-build
build_linux_36

00:13:12

64.0%
passed #181231
docker-build
build_linux_37

00:13:16

64.0%
passed #181228
macosx
build_macosx_36

00:17:56

64.0%
passed #181229
macosx
build_macosx_37

00:17:55

64.0%