Fix typo in anonymous user name (#663)

airsonic-main/src/main/java/org/airsonic/player/security/JWTAuthenticationToken.java

@@ -6,9 +6,12 @@ import org.springframework.security.core.GrantedAuthority;
 import java.util.Collection;
 
 public class JWTAuthenticationToken extends AbstractAuthenticationToken {
+
     private final String token;
     private String requestedPath;
 
+    public static final String USERNAME_ANONYMOUS = "anonymous";
+
     public JWTAuthenticationToken(Collection<? extends GrantedAuthority> authorities, String token, String requestedPath) {
         super(authorities);
         this.token = token;
@@ -22,7 +25,7 @@ public class JWTAuthenticationToken extends AbstractAuthenticationToken {
 
     @Override
     public Object getPrincipal() {
-        return "GERNIC_JWT_PRINICPLE";
+        return USERNAME_ANONYMOUS;
     }
 
     public String getRequestedPath() {