Fix gcc missing case warnings

Gcc ASSERT() missing cases are impossible

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

lib/libzfs/libzfs_changelist.c

@@ -131,6 +131,8 @@ changelist_prefix(prop_changelist_t *clp)
 			case ZFS_PROP_SHARESMB:
 				(void) zfs_unshare_smb(cn->cn_handle, NULL);
 				break;
+			default:
+				break;
 			}
 		}
 	}

lib/libzfs/libzfs_dataset.c

@@ -72,6 +72,8 @@ zfs_type_to_name(zfs_type_t type)
 		return (dgettext(TEXT_DOMAIN, "snapshot"));
 	case ZFS_TYPE_VOLUME:
 		return (dgettext(TEXT_DOMAIN, "volume"));
+	default:
+		break;
 	}
 
 	return (NULL);
@@ -180,6 +182,8 @@ zfs_validate_name(libzfs_handle_t *hdl, const char *path, int type,
 				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 				    "reserved disk name"));
 				break;
+			default:
+				break;
 			}
 		}
 
@@ -1015,6 +1019,8 @@ badlabel:
 					    "component of '%s' is too long"),
 					    propname);
 					break;
+				default:
+					break;
 				}
 				(void) zfs_error(hdl, EZFS_BADPROP, errbuf);
 				goto error;
@@ -1139,6 +1145,8 @@ badlabel:
 		case ZFS_PROP_NORMALIZE:
 			chosen_normal = (int)intval;
 			break;
+		default:
+			break;
 		}
 
 		/*
@@ -1187,6 +1195,8 @@ badlabel:
 					goto error;
 				}
 				break;
+			default:
+				break;
 			}
 		}
 	}
@@ -1674,6 +1684,8 @@ get_numeric_property(zfs_handle_t *zhp, zfs_prop_t prop, zprop_source_t *src,
 		mntopt_on = MNTOPT_NBMAND;
 		mntopt_off = MNTOPT_NONBMAND;
 		break;
+	default:
+		break;
 	}
 
 	/*

lib/libzfs/libzfs_pool.c

@@ -178,6 +178,8 @@ char *
 zpool_state_to_name(vdev_state_t state, vdev_aux_t aux)
 {
 	switch (state) {
+	default:
+		break;
 	case VDEV_STATE_CLOSED:
 	case VDEV_STATE_OFFLINE:
 		return (gettext("OFFLINE"));
@@ -421,6 +423,8 @@ zpool_valid_proplist(libzfs_handle_t *hdl, const char *poolname,
 		 * Perform additional checking for specific properties.
 		 */
 		switch (prop) {
+		default:
+			break;
 		case ZPOOL_PROP_VERSION:
 			if (intval < version || intval > SPA_VERSION) {
 				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
@@ -730,7 +734,10 @@ zpool_name_valid(libzfs_handle_t *hdl, boolean_t isopen, const char *pool)
 				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 				    "multiple '@' delimiters in name"));
 				break;
-
+			case NAME_ERR_NO_AT:
+				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
+				    "permission set is missing '@'"));
+				break;
 			}
 		}
 		return (B_FALSE);