travis: update for Oracle JDK 7
travis: update for Oracle JDK 7

pmoerenhout/jsmpp-1,opentelecoms-org/jsmpp,openam-org-ru/org.jsmpp,openam-org-ru/org.jsmpp,kamslooce/jsmpp,amdtelecom/jsmpp,opentelecoms-org/jsmpp,pmoerenhout/jsmpp-1,amdtelecom/jsmpp,kamslooce/jsmpp