Few minor userspace polishes on caps for kernel changes

conts/test/src/capability.c

@@ -119,9 +119,6 @@ void cap_print(struct capability *cap)
 	case CAP_RTYPE_CONTAINER:
 		printf("Capability resource type:\t%s\n", "Container");
 		break;
-	case CAP_RTYPE_UMUTEX:
-		printf("Capability resource type:\t%s\n", "Mutex");
-		break;
 	case CAP_RTYPE_VIRTMEM:
 		printf("Capability resource type:\t%s\n", "Virtual Memory");
 		break;

conts/test/src/captest.c

@@ -110,7 +110,7 @@ int capability_test(void)
 	 * group
 	 */
 	if ((err = l4_capability_control(CAP_CONTROL_SHARE,
-					 CAP_SHARE_GROUP, 0)) < 0) {
+					 CAP_SHARE_CONTAINER, 0)) < 0) {
 		printf("Sharing capability with thread group failed.\n");
 		goto out_err;
 	}

src/api/mutex.c

@@ -245,10 +245,8 @@ int sys_mutex_control(unsigned long mutex_address, int mutex_op)
 	/*
 	 * Find and check physical address for virtual mutex address
 	 *
-	 * FIXME: Could we check this as a capability? Perhaps not
-	 * since not always the caller but its pager possesses
-	 * relevant memory capability. Maybe check on behalf of
-	 * its pager?
+	 * NOTE: This is a shortcut to capability checking on memory
+	 * capabilities of current task.
 	 */
 	if (!(mutex_physical =
 		virt_to_phys_by_pgd(mutex_address,