1. Use 'dat' extension, because it is handled in Makefile.am;
2. Fix typo: the bug id is 35469, not 35649.
mysql-test/std_data/bug35469.dat:
Rename: mysql-test/std_data/bug35649.data -> mysql-test/std_data/bug35469.dat
mysql-test/r/loaddata.result:
Update result file.
mysql-test/t/loaddata.test:
1. Use 'dat' extension, because it is handled in Makefile.am;
2. Fix typo: the bug id is 35469, not 35649.
