Added Codecov to travis after_success.
Added Codecov to travis after_success.

cdillard/SwiftLint,firebase/SwiftLint,Johnykutty/SwiftLint,realm/SwiftLint,Johnykutty/SwiftLint,wfleming/SwiftLint,realm/SwiftLint,lyft/SwiftLint,jeffreybergier/SwiftLint,firebase/SwiftLint,daniel-beard/SwiftLint,jeffreybergier/SwiftLint,wfleming/SwiftLint,jeffreybergier/SwiftLint,victorpimentel/SwiftLint,daniel-beard/SwiftLint,firebase/SwiftLint,lyft/SwiftLint,cdillard/SwiftLint,victorpimentel/SwiftLint,victorpimentel/SwiftLint,lyft/SwiftLint,firebase/SwiftLint,Johnykutty/SwiftLint,lyft/SwiftLint,Johnykutty/SwiftLint,realm/SwiftLint,victorpimentel/SwiftLint,realm/SwiftLint,jeffreybergier/SwiftLint