Fix Apache license headers

...ngframework/samples/petclinic/system/CrashController.java

...framework/samples/petclinic/system/WelcomeController.java

.../org/springframework/samples/petclinic/vet/Specialty.java

...n/java/org/springframework/samples/petclinic/vet/Vet.java

.../springframework/samples/petclinic/vet/VetController.java

.../springframework/samples/petclinic/vet/VetRepository.java

.../java/org/springframework/samples/petclinic/vet/Vets.java

...va/org/springframework/samples/petclinic/visit/Visit.java

...ingframework/samples/petclinic/visit/VisitRepository.java

src/main/less/petclinic.less

...ramework/samples/petclinic/PetclinicIntegrationTests.java

...ringframework/samples/petclinic/model/ValidatorTests.java

...amework/samples/petclinic/owner/OwnerControllerTests.java

...framework/samples/petclinic/owner/PetControllerTests.java

...mework/samples/petclinic/owner/PetTypeFormatterTests.java

...amework/samples/petclinic/owner/VisitControllerTests.java

...amework/samples/petclinic/service/ClinicServiceTests.java

...pringframework/samples/petclinic/service/EntityUtils.java

...mework/samples/petclinic/system/CrashControllerTests.java

...ngframework/samples/petclinic/vet/VetControllerTests.java