Zappa should fail if cannot download dependency packages

Context

Dependencies (such as psycopg2) is needed by the app. If Zappa cannot download or get it from cache, then update/deploy should fail.

Expected Behavior

Failed deploy.

Actual Behavior

The psycopg2 download timed out, then continue deploying a broken app.

Steps to Reproduce

1. zappa update prd

(make the network unstable to fail a dependency, but then stable enough to continue deploying the app)

Your Environment

Zappa x Python 3.6 in Anaconda Windows 10 64-bit

• Zappa version used: 0.45.1
• Operating System and Python version: python 3.6.3 anaconda windows 10 64-bit
• The output of pip freeze:

argcomplete==1.9.2
base58==0.2.4
boto3==1.4.7
botocore==1.7.43
certifi==2017.11.5
chardet==3.0.4
click==6.7
Django==1.11.7
docutils==0.14
durationpy==0.5
future==0.16.0
hjson==3.0.1
idna==2.6
jmespath==0.9.3
kappa==0.6.0
lambda-packages==0.19.0
placebo==0.8.1
psycopg2==2.7.3.2
python-dateutil==2.6.1
python-slugify==1.2.4
pytz==2017.3
PyYAML==3.12
requests==2.18.4
s3transfer==0.1.11
six==1.11.0
toml==0.9.3
tqdm==4.19.1
troposphere==2.0.2
Unidecode==0.4.21
urllib3==1.22
Werkzeug==0.12
wsgi-request-logger==0.4.6
zappa==0.45.1

• Link to your project (optional):
• Your zappa_settings.py:

{
    "prd": {
        "aws_region": "us-east-1",
        "django_settings": "matagarudabot.settings",
        "profile_name": "default",
        "project_name": "matagarudabot",
        "runtime": "python3.6",
        "s3_bucket": "samaraedu-code",
        "memory_size": 128,
        "keep_warm": true
    }
}