[hotfix] prepend "mvn-" to Travis log files
[hotfix] prepend "mvn-" to Travis log files

This is just a safety precaution in case future tests forget to include the
mvn.forkNumber property in the argLine. In that case, the log file would have
been ".log" and omitted from the log files package that is uploaded for further
inspection.

GJL/flink,fanzhidongyzby/flink,StephanEwen/incubator-flink,tillrohrmann/flink,clarkyzl/flink,haohui/flink,fanyon/flink,mtunique/flink,fanzhidongyzby/flink,wwjiang007/flink,kl0u/flink,GJL/flink,wwjiang007/flink,jinglining/flink,kaibozhou/flink,haohui/flink,greghogan/flink,zjureel/flink,fhueske/flink,wwjiang007/flink,tillrohrmann/flink,gyfora/flink,zjureel/flink,zentol/flink,haohui/flink,godfreyhe/flink,jinglining/flink,shaoxuan-wang/flink,WangTaoTheTonic/flink,twalthr/flink,mbode/flink,yew1eb/flink,xccui/flink,darionyaphet/flink,haohui/flink,tony810430/flink,zohar-mizrahi/flink,mbode/flink,greghogan/flink,gyfora/flink,mylog00/flink,mbode/flink,aljoscha/flink,tony810430/flink,fanyon/flink,zhangminglei/flink,ueshin/apache-flink,tillrohrmann/flink,GJL/flink,zjureel/flink,zohar-mizrahi/flink,gyfora/flink,ueshin/apache-flink,apache/flink,clarkyzl/flink,zohar-mizrahi/flink,bowenli86/flink,tillrohrmann/flink,hequn8128/flink,mbode/flink,ueshin/apache-flink,zjureel/flink,darionyaphet/flink,lincoln-lil/flink,zhangminglei/flink,yew1eb/flink,zimmermatt/flink,tzulitai/flink,StephanEwen/incubator-flink,tzulitai/flink,sunjincheng121/flink,zjureel/flink,rmetzger/flink,PangZhi/flink,darionyaphet/flink,zohar-mizrahi/flink,clarkyzl/flink,hequn8128/flink,rmetzger/flink,WangTaoTheTonic/flink,mtunique/flink,tony810430/flink,bowenli86/flink,mbode/flink,shaoxuan-wang/flink,xccui/flink,Xpray/flink,xccui/flink,gustavoanatoly/flink,godfreyhe/flink,StephanEwen/incubator-flink,apache/flink,sunjincheng121/flink,gyfora/flink,PangZhi/flink,zhangminglei/flink,StephanEwen/incubator-flink,fanyon/flink,mylog00/flink,hequn8128/flink,sunjincheng121/flink,rmetzger/flink,lincoln-lil/flink,gustavoanatoly/flink,jinglining/flink,zentol/flink,rmetzger/flink,greghogan/flink,zimmermatt/flink,tzulitai/flink,greghogan/flink,GJL/flink,shaoxuan-wang/flink,rmetzger/flink,PangZhi/flink,xccui/flink,hwstreaming/flink,gustavoanatoly/flink,fhueske/flink,zentol/flink,lincoln-lil/flink,fanzhidongyzby/flink,kaibozhou/flink,tillrohrmann/flink,gyfora/flink,sunjincheng121/flink,GJL/flink,tony810430/flink,WangTaoTheTonic/flink,hequn8128/flink,wwjiang007/flink,kaibozhou/flink,zentol/flink,twalthr/flink,gyfora/flink,aljoscha/flink,hongyuhong/flink,kaibozhou/flink,kl0u/flink,kl0u/flink,fanyon/flink,jinglining/flink,bowenli86/flink,twalthr/flink,greghogan/flink,hwstreaming/flink,hequn8128/flink,yew1eb/flink,hongyuhong/flink,aljoscha/flink,apache/flink,gustavoanatoly/flink,jinglining/flink,tzulitai/flink,twalthr/flink,kaibozhou/flink,mtunique/flink,WangTaoTheTonic/flink,bowenli86/flink,zimmermatt/flink,yew1eb/flink,wwjiang007/flink,tony810430/flink,zimmermatt/flink,bowenli86/flink,fhueske/flink,twalthr/flink,zentol/flink,Xpray/flink,zentol/flink,zjureel/flink,rmetzger/flink,Xpray/flink,hwstreaming/flink,hongyuhong/flink,apache/flink,WangTaoTheTonic/flink,hwstreaming/flink,apache/flink,darionyaphet/flink,yew1eb/flink,hequn8128/flink,zhangminglei/flink,godfreyhe/flink,kl0u/flink,tillrohrmann/flink,wwjiang007/flink,fanzhidongyzby/flink,StephanEwen/incubator-flink,gustavoanatoly/flink,tzulitai/flink,ueshin/apache-flink,hwstreaming/flink,shaoxuan-wang/flink,shaoxuan-wang/flink,jinglining/flink,kaibozhou/flink,greghogan/flink,godfreyhe/flink,zohar-mizrahi/flink,PangZhi/flink,lincoln-lil/flink,aljoscha/flink,mylog00/flink,hongyuhong/flink,Xpray/flink,apache/flink,mtunique/flink,apache/flink,fanyon/flink,aljoscha/flink,lincoln-lil/flink,zhangminglei/flink,zjureel/flink,StephanEwen/incubator-flink,zimmermatt/flink,kl0u/flink,xccui/flink,clarkyzl/flink,sunjincheng121/flink,godfreyhe/flink,xccui/flink,kl0u/flink,xccui/flink,lincoln-lil/flink,darionyaphet/flink,sunjincheng121/flink,fanzhidongyzby/flink,fhueske/flink,bowenli86/flink,mylog00/flink,rmetzger/flink,wwjiang007/flink,ueshin/apache-flink,GJL/flink,godfreyhe/flink,shaoxuan-wang/flink,tillrohrmann/flink,haohui/flink,aljoscha/flink,godfreyhe/flink,tony810430/flink,clarkyzl/flink,PangZhi/flink,twalthr/flink,zentol/flink,fhueske/flink,Xpray/flink,tzulitai/flink,hongyuhong/flink,tony810430/flink,lincoln-lil/flink,mtunique/flink,twalthr/flink,gyfora/flink,fhueske/flink,mylog00/flink