Allow PHP 5.3.3 to fail

[whikloj]

JIRA Ticket: https://jira.duraspace.org/browse/ISLANDORA-2424

What does this Pull Request do?

Allows PHP 5.3.3. to fail in Travis without marking the build as a failure.

How should this be tested?

Travis will test

Additional Notes:

• Does this change the interface, add a new feature, or otherwise change behaviours that would require updating documentation? no
• Does this change add any new dependencies? no
• Does this change require any other modifications to be made to the repository (ie. Regeneration activity, etc.)? no
• Could this change impact execution of existing code? no

Interested parties

@Islandora/7-x-1-x-committers