set missing username in UserProfile

spring-social-linkedin/src/main/java/org/springframework/social/linkedin/connect/LinkedInAdapter.java

@@ -50,6 +50,7 @@ public void setConnectionValues(LinkedIn linkedin, ConnectionValues values) {
 	public UserProfile fetchUserProfile(LinkedIn linkedin) {
 		LinkedInProfile profile = linkedin.profileOperations().getUserProfile();
 		return new UserProfileBuilder()
+				.setUsername(profile.getId())
 				.setName(profile.getFirstName() + " " + profile.getLastName())
 				.setEmail(profile.getEmailAddress())
 				.build();