Fix GCC 6.3.0 warnings.

storage/innobase/fsp/fsp0fsp.cc

@@ -2801,6 +2801,7 @@ fsp_reserve_free_extents(
 		}
 	} else {
 		ut_a(alloc_type == FSP_CLEANING);
+		reserve = 0;
 	}
 
 	success = fil_space_reserve_free_extents(space, n_free, n_ext);

storage/innobase/row/row0ftsort.cc

@@ -620,7 +620,6 @@ fts_parallel_tokenization(
 	mem_heap_t*		blob_heap = NULL;
 	fts_doc_t		doc;
 	dict_table_t*		table = psort_info->psort_common->new_table;
-	dict_field_t*		idx_field;
 	fts_tokenize_ctx_t	t_ctx;
 	ulint			retried = 0;
 	dberr_t			error = DB_SUCCESS;
@@ -642,9 +641,6 @@ fts_parallel_tokenization(
 	doc.charset = fts_index_get_charset(
 		psort_info->psort_common->dup->index);
 
-	idx_field = dict_index_get_nth_field(
-		psort_info->psort_common->dup->index, 0);
-
 	block = psort_info->merge_block;
 	zip_size = dict_table_zip_size(table);
 

storage/xtradb/fsp/fsp0fsp.cc

@@ -2810,6 +2810,7 @@ fsp_reserve_free_extents(
 		}
 	} else {
 		ut_a(alloc_type == FSP_CLEANING);
+		reserve = 0;
 	}
 
 	success = fil_space_reserve_free_extents(space, n_free, n_ext);