<rdar://problem/15936507>

ScriptInterpreterPython caches the lldb.embedded_interpreter module, and since it caches it in a refcounting-safe PythonObject, the refcount will appropriately go down 1 every time a ScriptInterpreterPython is deallocated
However, we were only importing the module once - in InitializePrivate(). In a handful of interpreter creations, the refcount on the run_one_line function would end up at 0, causing LLDB to crash
This fixes it by also importing the module for every interpreter, which ensures correct refcounting

llvm-svn: 200816