Memory leak fix. (Coverity #746739)

src/libknot/zone/zone-diff.c

@@ -443,7 +443,7 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 		if (tmp_rdata_copy == NULL) {
 			dbg_zonediff("zone diff: diff_rdata: Cannot copy "
 			             "RDATA (Different TTLs).\n");
-			/* TODO cleanup. */
+			knot_rrset_free(&to_remove);
 			return KNOT_ENOMEM;
 		}
 		int ret = knot_rrset_add_rdata(to_remove, tmp_rdata_copy);
@@ -451,7 +451,8 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 			dbg_zonediff("zone diff: diff_rdata: Cannot add "
 			             "RDATA to RRSet. Reason: %s\n",
 			             knot_strerror(ret));
-			/* TODO cleanup. */
+			knot_rdata_free(&tmp_rdata_copy);
+			knot_rrset_free(&to_remove);
 			return ret;
 		}
 	}
@@ -486,6 +487,7 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 		if (ret != KNOT_EOK) {
 			dbg_zonediff("zone_diff: diff_rdata: Could not get changes. "
 			             "Error: %s.\n", knot_strerror(ret));
+			knot_rrset_deep_free(&to_add, 1, 1, 1);
 			return ret;
 		}
 	} else {
@@ -517,7 +519,6 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 				dbg_zonediff("zone diff: diff_rdata: Cannot copy "
 				             "RDATA (Different TTLs).\n");
 				knot_rrset_deep_free(&to_add, 1, 1, 1);
-				knot_rrset_deep_free(&to_remove, 1, 1, 1);
 				return KNOT_ENOMEM;
 			}
 			int ret = knot_rrset_add_rdata(to_add, tmp_rdata_copy);
@@ -526,7 +527,6 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 				             "RDATA to RRSet. Reason: %s\n",
 				             knot_strerror(ret));
 				knot_rrset_deep_free(&to_add, 1, 1, 1);
-				knot_rrset_deep_free(&to_remove, 1, 1, 1);
 				return ret;
 			}
 		}
@@ -538,6 +538,7 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 		knot_rrset_deep_free(&to_add, 1, 1, 1);
 		dbg_zonediff("zone_diff: diff_rdata: Could not remove RRs. "
 		             "Error: %s.\n", knot_strerror(ret));	
+		knot_rrset_deep_free(&to_add, 1, 1, 1);
 		return ret;
 	}