Signed-off-by: Bob Schmitz III schmitzr1984@gmail.com

Description

• Fixed shell TEST_ENABLED conditional syntax to be POSIX friendly.
• Changed multi-line conditional to use more condensed ternary operation.

Motivation and Context

This fixes a syntax error occurring in Debian based image templates which uses dash as the default shell.

• I have raised an issue to propose this change (required)
• My issue has received approval from the maintainers or lead with the design/approved label

Closes #53

How Has This Been Tested?

1. Created stripped Dockerfiles for both python:3.7-alpine and python:3.7-slim-buster (see https://gist.github.com/rgschmitz1/1cc3f375e582433dc80191b87d2e103e for detailed log).
2. Issued docker build command for both base images.
3. Tested fix in templates using the openfaas documentation for creating new functions, verified TEST_ENABLED works as described in documentation when set to "false".

• FaaS-CLI version ( Full output from: faas-cli version ):

  ___                   _____           ____
 / _ \ _ __   ___ _ __ |  ___|_ _  __ _/ ___|
| | | | '_ \ / _ \ '_ \| |_ / _` |/ _` \___ \
| |_| | |_) |  __/ | | |  _| (_| | (_| |___) |
 \___/| .__/ \___|_| |_|_|  \__,_|\__,_|____/
      |_|

CLI:
 commit:  b1c09c0243f69990b6c81a17d7337f0fd23e7542
 version: 0.14.2

• Docker version docker version (e.g. Docker 17.0.05 ):

Docker version 20.10.14, build a224086

• Operating System and version (e.g. Linux, Windows, MacOS):

NAME="Ubuntu"
VERSION="20.04.4 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.4 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s
• I have added tests to cover my changes.
• All new and existing tests passed.