Fix rocksdb.tbl_opt_data_index_dir on a mac

storage/rocksdb/mysql-test/rocksdb/t/tbl_opt_data_index_dir.test

@@ -13,10 +13,16 @@
 DROP TABLE IF EXISTS t1;
 --enable_warnings
 
+# On a Mac, strerror()  prints "Unknown error: nn", as 
+#  opposed to "Unknown error nn" on Linux/etc.
+# Replacing 'error:' with 'error' below to make the output uniform.
+
+--replace_result error: error
 --error ER_CANT_CREATE_TABLE
 CREATE TABLE t1 (a INT PRIMARY KEY, b CHAR(8)) ENGINE=rocksdb DATA DIRECTORY = '/foo/bar/data';
 show warnings;
 
+--replace_result error: error
 --error ER_CANT_CREATE_TABLE
 CREATE TABLE t1 (a INT PRIMARY KEY, b CHAR(8)) ENGINE=rocksdb INDEX DIRECTORY = '/foo/bar/index';
 show warnings;
@@ -25,6 +31,7 @@ show warnings;
 # Verify that we'll get the same error codes when using the partitions.
 #
 
+--replace_result error: error
 --error ER_CANT_CREATE_TABLE
 CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY) ENGINE=rocksdb PARTITION BY RANGE (id)
 (
@@ -36,6 +43,7 @@ CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY) ENGINE=rocksdb PARTITION BY RANGE
 );
 show warnings;
 
+--replace_result error: error
 --error ER_CANT_CREATE_TABLE
 CREATE TABLE t1 (id int not null primary key) ENGINE=rocksdb PARTITION BY RANGE (id)
 (