Fix `make requirements` on osx
Fix `make requirements` on osx

Beforehand, it was throwing
```
# Setup PYTHONPATH in bash activate script...
# Delete existing entries (if any)
sed -i '/_OLD_PYTHONPATHp/d' virtualenv-osx/bin/activate
sed: 1: "virtualenv-osx/bin/acti ...": invalid command code v
make: *** [virtualenv] Error 1
```

Plexxi/st2,StackStorm/st2,Plexxi/st2,StackStorm/st2,nzlosh/st2,nzlosh/st2,nzlosh/st2,nzlosh/st2,StackStorm/st2,Plexxi/st2,StackStorm/st2,Plexxi/st2