update travis logic to avoid signatures
update travis logic to avoid signatures

Djimmer/obts,xyzr0482/openbts,RangeNetworks/openbts,WindyCitySDR/openbts,Djimmer/obts,hongyunnchen/openbts,WindyCitySDR/openbts,RangeNetworks/openbts,maxifree/openbts,WindyCitySDR/openbts,hongyunnchen/openbts,brunoflce/pessoalopenBTS,endaga/openbts,maxifree/openbts,dhenyjarasandy/openbts,Djimmer/obts,brunoflce/pessoalopenBTS,WindyCitySDR/openbts,endaga/openbts,endaga/openbts,brunoflce/pessoalopenBTS,brunoflce/pessoalopenBTS,brunoflce/pessoalopenBTS,xyzr0482/openbts,RangeNetworks/openbts,WindyCitySDR/openbts,RangeNetworks/openbts,xyzr0482/openbts,xyzr0482/openbts,dhenyjarasandy/openbts,maxifree/openbts,endaga/openbts,Djimmer/obts,endaga/openbts,hongyunnchen/openbts,hongyunnchen/openbts,RangeNetworks/openbts,maxifree/openbts,dhenyjarasandy/openbts,dhenyjarasandy/openbts,hongyunnchen/openbts,RangeNetworks/openbts,xyzr0482/openbts,Djimmer/obts,dhenyjarasandy/openbts,maxifree/openbts,Djimmer/obts