Removed compiler warnings from tokudb

- Backport from 10.4

Author: montywi

storage/tokudb/tokudb_sysvars.cc

@@ -892,6 +892,7 @@ static MYSQL_THDVAR_ULONGLONG(
  1);
 #endif // defined(TOKU_INCLUDE_RFR) && TOKU_INCLUDE_RFR
 
+#if defined(TOKU_INCLUDE_UPSERT)
 static MYSQL_THDVAR_BOOL(
  enable_fast_update,
  PLUGIN_VAR_THDLOCAL,
@@ -907,6 +908,7 @@ static MYSQL_THDVAR_BOOL(
  NULL,
  NULL,
  false);
+#endif
 
 #if TOKU_INCLUDE_XA
 static MYSQL_THDVAR_BOOL(