qapi: Factor QAPISchemaParser._include() out of .__init__()

                continue

            expr = self.get_expr(False)

            if isinstance(expr, dict) and "include" in expr:

            if 'include' in expr:

                if len(expr) != 1:

                    raise QAPISemError(info, "Invalid 'include' directive")

                include = expr["include"]

                if not isinstance(include, str):

                    raise QAPISemError(info,

                                       "Value of 'include' must be a string")

                incl_abs_fname = os.path.join(os.path.dirname(abs_fname),

                                              include)

                self._include(include, info, os.path.dirname(abs_fname),

                              previously_included)

            else:

                expr_elem = {'expr': expr,

                             'info': info}

                if (self.docs

                        and self.docs[-1].info['file'] == fname

                        and not self.docs[-1].expr):

                    self.docs[-1].expr = expr

                    expr_elem['doc'] = self.docs[-1]

                self.exprs.append(expr_elem)

    def _include(self, include, info, base_dir, previously_included):

        incl_abs_fname = os.path.join(base_dir, include)

        # catch inclusion cycle

        inf = info

        while inf:

            if incl_abs_fname == os.path.abspath(inf['file']):

                        raise QAPISemError(info, "Inclusion loop for %s"

                                           % include)

                raise QAPISemError(info, "Inclusion loop for %s" % include)

            inf = inf['parent']

        # skip multiple include of the same file

        if incl_abs_fname in previously_included:

                    continue

            return

        try:

            fobj = open(incl_abs_fname, 'r')

        except IOError as e:

            raise QAPISemError(info, '%s: %s' % (e.strerror, include))

                exprs_include = QAPISchemaParser(fobj, previously_included,

                                                 info)

        exprs_include = QAPISchemaParser(fobj, previously_included, info)

        self.exprs.extend(exprs_include.exprs)

        self.docs.extend(exprs_include.docs)

            else:

                expr_elem = {'expr': expr,

                             'info': info}

                if (self.docs

                        and self.docs[-1].info['file'] == fname

                        and not self.docs[-1].expr):

                    self.docs[-1].expr = expr

                    expr_elem['doc'] = self.docs[-1]

                self.exprs.append(expr_elem)

    def accept(self, skip_comment=True):

        while True: