disable DEVELOPER

stage-qa target fails with non-zero exit status when non-fatal error is
found, such as " Error: /usr/bin/perl is an invalid shebang you need
USES=shebangfix for share/git-core/contrib/hooks/setgitperms.perl". this
target is very useful for QA but many ports probably have some kind of
QA error. disable this as it is not our purpose to fix all these ports.
Merge branch 'master' of github.com:reallyenglish/reallyenglish-tinderbox-scripts