remove extraneous step from travis script

Author: morganchen12

.travis.yml

@@ -6,8 +6,7 @@ xcode_scheme: FirebaseUITests
 script: xcodebuild -workspace FirebaseUI.xcworkspace
   -scheme FirebaseUI
   -sdk iphonesimulator
-  -destination 'platform=iOS Simulator,name=iPhone 6s'
-  build 
+  -destination 'platform=iOS Simulator,name=iPhone 6s' 
   test
   ONLY_ACTIVE_ARCH=NO
   CODE_SIGN_IDENTITY=""