Fix other occurences of oscap_htable_add

If the hash table owns its elements, its responsible for freeing
them. The callers of oscap_htable_add rely on the fact that the
elements will be later freed by oscap_htable_free. However, if
oscap_htable_add fails to insert the elements to the table,
then the caller needs to free them.

Author: jan-cerny

src/DS/rds.c

@@ -888,7 +888,10 @@ int ds_rds_create(const char* sds_file, const char* xccdf_result_file, const cha
 				result = -1;
 				oscap_source_free(oval_source);
 			} else {
-				oscap_htable_add(oval_result_sources, *oval_result_files, oval_source);
+				if (!oscap_htable_add(oval_result_sources, *oval_result_files, oval_source)) {
+					result = -1;
+					oscap_source_free(oval_source);
+				}
 			}
 			oval_result_files++;
 		}

src/OVAL/oval_generator.c

@@ -171,7 +171,10 @@ void oval_generator_update_timestamp(struct oval_generator *generator)
 
 void oval_generator_add_platform_schema_version(struct oval_generator *generator, const char *platform, const char *schema_version)
 {
-	oscap_htable_add(generator->platform_schema_versions, platform, oscap_strdup(schema_version));
+	char *schema_version_dup = oscap_strdup(schema_version);
+	if (!oscap_htable_add(generator->platform_schema_versions, platform, schema_version_dup)) {
+		free(schema_version_dup);
+	}
 }