"upgrade" failed on windows, because of lower_case_table_name.
This fix changes letters to lower case, not to depend on OS.

Note, this change does not affect coverage of 
Bug N 17142 "Crash if create with encoded name",
which the test war originally written for.


mysql-test/r/upgrade.result:
  Changing "P" to "p" not to depend on lower_case_table_name
mysql-test/t/upgrade.test:
  Changing "P" to "p" not to depend on lower_case_table_name