remove explicit python version to avoid conflict with virtualenv
remove explicit python version to avoid conflict with virtualenv

schieb/angr,f-prettyland/angr,f-prettyland/angr,iamahuman/angr,angr/angr,tyb0807/angr,f-prettyland/angr,tyb0807/angr,angr/angr,schieb/angr,angr/tracer,tyb0807/angr,schieb/angr,iamahuman/angr,angr/angr,iamahuman/angr