NO-JIRA: [ruby] Put external RUBYLIB at end of path for tests
NO-JIRA: [ruby] Put external RUBYLIB at end of path for tests

Avoid picking up installed proton packages when testing.

kgiusti/qpid-proton,ChugR/qpid-proton,kgiusti/qpid-proton,gemmellr/qpid-proton,ChugR/qpid-proton,kgiusti/qpid-proton,ssorj/qpid-proton,alanconway/qpid-proton,apache/qpid-proton,astitcher/qpid-proton,ssorj/qpid-proton,alanconway/qpid-proton,ChugR/qpid-proton,alanconway/qpid-proton,ssorj/qpid-proton,gemmellr/qpid-proton,apache/qpid-proton,astitcher/qpid-proton,apache/qpid-proton,ChugR/qpid-proton,astitcher/qpid-proton,alanconway/qpid-proton,alanconway/qpid-proton,gemmellr/qpid-proton,gemmellr/qpid-proton,ChugR/qpid-proton,ssorj/qpid-proton,ssorj/qpid-proton,gemmellr/qpid-proton,kgiusti/qpid-proton,apache/qpid-proton,apache/qpid-proton,ssorj/qpid-proton,astitcher/qpid-proton,ChugR/qpid-proton,astitcher/qpid-proton,kgiusti/qpid-proton,kgiusti/qpid-proton,gemmellr/qpid-proton,apache/qpid-proton,astitcher/qpid-proton,alanconway/qpid-proton