fix the sys not found error when importing sd_samplers that appeared after PR

assert sd_path is not None, "Couldn't find Stable Diffusion in any of: " + str(possible_sd_paths)

path_dirs = [

    (sd_path, 'ldm', 'Stable Diffusion'),

    (os.path.join(sd_path, '../taming-transformers'), 'taming', 'Taming Transformers'),

    (os.path.join(sd_path, '../CodeFormer'), 'inference_codeformer.py', 'CodeFormer'),

    (os.path.join(sd_path, '../BLIP'), 'models/blip.py', 'BLIP'),

    (os.path.join(sd_path, '../latent-diffusion'), 'LDSR.py', 'LDSR'),

    (os.path.join(sd_path, '../k-diffusion'), 'k_diffusion/sampling.py', 'k_diffusion'),

    (sd_path, 'ldm', 'Stable Diffusion', []),

    (os.path.join(sd_path, '../taming-transformers'), 'taming', 'Taming Transformers', []),

    (os.path.join(sd_path, '../CodeFormer'), 'inference_codeformer.py', 'CodeFormer', []),

    (os.path.join(sd_path, '../BLIP'), 'models/blip.py', 'BLIP', []),

    (os.path.join(sd_path, '../latent-diffusion'), 'LDSR.py', 'LDSR', []),

    (os.path.join(sd_path, '../k-diffusion'), 'k_diffusion/sampling.py', 'k_diffusion', ["atstart"]),

]

paths = {}

for d, must_exist, what in path_dirs:

for d, must_exist, what, options in path_dirs:

    must_exist_path = os.path.abspath(os.path.join(script_path, d, must_exist))

    if not os.path.exists(must_exist_path):

        print(f"Warning: {what} not found at path {must_exist_path}", file=sys.stderr)

    else:

        d = os.path.abspath(d)

        if "atstart" in options:

            sys.path.insert(0, d)

        else:

            sys.path.append(d)

        paths[what] = d

import tqdm

from PIL import Image

import inspect

from modules.paths import paths

sys.path.insert(0, paths["k_diffusion"])

import k_diffusion.sampling

import ldm.models.diffusion.ddim

import ldm.models.diffusion.plms