When running tests in Travis and 'gem install' and 'npm install' fail, retry at most 2 more times.
When running tests in Travis and 'gem install' and 'npm install' fail, retry at most 2 more times.

This mitigates most temporary network problems.

kewaunited/passenger,kewaunited/passenger,kewaunited/passenger,phusion/passenger,kewaunited/passenger,kewaunited/passenger,cgvarela/passenger,clemensg/passenger,phusion/passenger,cgvarela/passenger,phusion/passenger,clemensg/passenger,antek-drzewiecki/passenger,clemensg/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,kewaunited/passenger,cgvarela/passenger,cgvarela/passenger,phusion/passenger,clemensg/passenger,clemensg/passenger,kewaunited/passenger,phusion/passenger,antek-drzewiecki/passenger,clemensg/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,phusion/passenger,cgvarela/passenger,antek-drzewiecki/passenger,cgvarela/passenger,cgvarela/passenger,clemensg/passenger,kewaunited/passenger,cgvarela/passenger,phusion/passenger,phusion/passenger,clemensg/passenger