Fix test failures related to commit 1230f34.
Fix test failures related to commit 1230f34.

Summary:
Fixed two test cases related to asset builder.

1. 'asset_with_invalid_destination' test case was failing because of a
   'test' project name. Changed the name to 'nonexistent_project'

2. 'asset_with_invalid_makefile' test case was failing because of
   improper syntax of the subprocess call and the error code returned
   by the failure. Fixed the syntax and changed error code to 1 from 3.

Test Plan: ./src/python/test/test_dxasset.py TestDXBuildAsset

Reviewers: psung

Reviewed By: psung

Differential Revision: https://dnanexus.phacility.com/D952

dnanexus/dx-toolkit,jhuttner/dx-toolkit,jhuttner/dx-toolkit,jhuttner/dx-toolkit,dnanexus/dx-toolkit,jhuttner/dx-toolkit,jhuttner/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,jhuttner/dx-toolkit,jhuttner/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,jhuttner/dx-toolkit,dnanexus/dx-toolkit