Update Travis badge to show master branch.
Update Travis badge to show master branch.

[#101431742]

ryan-talley/cf-bigip-ctlr,dramich/cf-bigip-ctlr,dramich/cf-bigip-ctlr,dramich/cf-bigip-ctlr,ryan-talley/cf-bigip-ctlr,ryan-talley/cf-bigip-ctlr,ryan-talley/cf-bigip-ctlr,dramich/cf-bigip-ctlr