azure-storage-blob - sas tokens for azurite container invalid in version 2.1.0

- **Package Name**:
azure-storage-blob
- **Package Version**:
2.1.0
- **Operating System**:
OSX 10.15.5
- **Python Version**:
3.8
**Describe the bug**
sas tokens generated for files stored in azurite container (`arafato/azurite:2.6.5`) are invalid and container returns 403 response.
For same code and data, but with `azure-storage-blob==1.5.0` valid tokens are generated and data can be accessed.
(sas tokens generated for real azure storage blob are valid with `azure-storage-blob==2.1.0`)

**To Reproduce**
Steps to reproduce the behavior:

Sample code:
```
import datetime

import azure.storage.blob
import azure.storage.blob.sharedaccesssignature
import flask

APP = flask.Flask("my_app")

@APP.route("/")
def index():

# Account credentials for azurite container ccount
connection_string = "AccountName=devstoreaccount1;AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==;DefaultEndpointsProtocol=http;BlobEndpoint=http://127.0.0.1:10000/devstoreaccount1;QueueEndpoint=http://127.0.0.1:10001/devstoreaccount1;TableEndpoint=http://127.0.0.1:10002/devstoreaccount1;"
container_name = "sketchpad"
account_name = "devstoreaccount1"
account_key = "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw=="

shared_access = azure.storage.blob.sharedaccesssignature.BlobSharedAccessSignature(
account_name=account_name,
account_key=account_key)

blob_storage = azure.storage.blob.BlockBlobService(connection_string=connection_string)

urls = []

images_blobs = [blob for blob in blob_storage.list_blobs(container_name=container_name) if ".jpg" in blob.name]

for image_blob in images_blobs:

access_signature = shared_access.generate_blob(
container_name=container_name, blob_name=image_blob.name,
permission=azure.storage.blob.BlobPermissions.READ,
start=datetime.datetime.utcnow() - datetime.timedelta(minutes=10),
expiry=datetime.datetime.utcnow() + datetime.timedelta(hours=1),
content_type='image/jpeg'
)

url = blob_storage.make_blob_url(
container_name=container_name,
blob_name=image_blob.name,
sas_token=access_signature)

urls.append('Image here'.format(url))

images_data = "
".join(urls)

response = ("""


{}


""".format(images_data))

return response

APP.run(use_reloader=True)

```

**Expected behavior**
Generated URLs should be valid.

**Screenshots**
Access log (from azurite container) and URL generated for file `kitty_2.jpg` in container `sketchpad` with `azure-storage-blob==2.1.0`
```
GET /devstoreaccount1/sketchpad/kitty_2.jpg?st=2020-06-24T05%3A58%3A04Z&se=2020-06-24T07%3A08%3A04Z&sp=r&sv=2019-02-02&sr=b&rsct=image/jpeg&sig=f21aCsoNKYVAKql%2BwvLHalvx6SP5nxylxu4sBlak%2Bkk%3D 403 0.889 ms - 240
```

URL generated for the same file with `azure-storage-blob==1.5.0`:
```
GET /devstoreaccount1/sketchpad/kitty_2.jpg?st=2020-06-24T06%3A02%3A31Z&se=2020-06-24T07%3A12%3A31Z&sp=r&sv=2018-03-28&sr=b&rsct=image/jpeg&sig=uSO6uFlEVGJm8A9cJQ8bnZdHjapd3LmX4eFgSpy6sT0%3D 200 4.385 ms - 9767
```