changed cmake to use a new build type for drd Tokutek/ft-engine#48

This lets us use CMAKE_BUILD_TYPE=drd instead of hijacking
RelWithDebInfo.

Also, make RelWithDebInfo synonymous with Release so we can build
MySQL/MariaDB that way.

Refs Tokutek/ft-engine#40 Merge bulk fetch bugfix

Refs Tokutek/ft-engine#40 Fix bug with checking left/right ranges of bounded query and interaction with bulk fetch
Add regression test

Refs trac [t:6712], Refs Tokutek/ft-engine#40 When possible, optimize by only checking left or right bound during a bounded query

Refs trac 6712, Refs Tokutek/ft-engine#40 Reduce computation time when we read something out of bounds (do not look in other basement/leaf nodes)

Refs Tokutek/ft-engine#40 Rename c_restrict_to_range to c_set_bounds, delete c_pre_acquire_range_lock

Refs Tokutek/ft-engine/#40 Add c_restrict_to_range function to force cursor to keep track of prelocked range

available nodes are query-able.

Ignore any error caused by this

#17 fix closedir with null pointer bug in toku_get_version_of_logs_on_disk found by injecting open file errors

refs #25.  Fix (test-only) bug where db_env_set_toku_product_name would not get called for some tests because they were lower than ydb layer

db_env_set_toku_product_name