Fix RelWithAsserts build type, remove build type validation

This change fixes typo (RELEASEWITHASSERTS -> RELWITHASSERTS) that
prevented cmake from choosing right optimization flags.

In addition build type validation has been removed since some project
file generators (MSVC generator for example) support multiple build
types and there is no build type defined at gen time.

Change-Id: I1f4856c029eb9dbfd2a4b665f204da00bf68e7e4
1 file changed