Fix HttpSecurity logout JavaDoc

Removed error provoking extra logout() from example code

config/src/main/java/org/springframework/security/config/annotation/web/builders/HttpSecurity.java

@@ -719,7 +719,7 @@ public final class HttpSecurity extends
 	 * 		http.authorizeRequests().antMatchers("/**").hasRole("USER").and().formLogin()
 	 * 				.and()
 	 * 				// sample logout customization
-	 * 				.logout().logout().deleteCookies("remove").invalidateHttpSession(false)
+	 * 				.logout().deleteCookies("remove").invalidateHttpSession(false)
 	 * 				.logoutUrl("/custom-logout").logoutSuccessUrl("/logout-success");
 	 * 	}
 	 *
@@ -1245,4 +1245,4 @@ public final class HttpSecurity extends
 		}
 		return apply(configurer);
 	}
-}
+}