Sneha Ramesh Watharkar, according to the Django documentation, (https://docs.djangoproject.com/en/2.1/ref/databases/),
the mysqlclient is the recommended choice for MySQL for django. Also, python-mysqldb is seen to give trouble for python 3.
There are few other changes required, which I found while setting up a new EC2 ubuntu instance:
aptpackages=("python3" "python3-pip" "apache2" "libapache2-mod-wsgi-py3" "zlib1g-dev" "python-dev" "libmysqlclient-dev" "libjpeg-dev" "libpng-dev" "mysql-server")
pippackages=("wheel" "django==1.8" "Pillow" "social-auth-app-django" "whoosh" "ipython" "django-haystack==2.2" "mysqlclient")
The script ran flawlessly on the machine. Didnt face issues even if some packages were already installed.