Bugs#17647: Trouble with "create database"

Problem:
if a user was granted privileges on database "d1",
it also was able to act on "D1" (i.e. in upper case),
even on Unix with case sensitive file system.

Fix:
Initialize grant hash to use binary comparison
if lower_case_file_system is not set (on most unixes),
and case insensitive comparison otherwise (Windows, MacOSX).

mysql-test/include/have_case_sensitive_file_system.inc

@@ -0,0 +1,4 @@
+--require r/case_sensitive_file_system.require
+--disable_query_log
+show variables like "lower_case_file_system";
+--enable_query_log