Fix CMake error in inspect build.
Fix CMake error in inspect build.

Fix var name typo.

BUG=aomedia:1038

Change-Id: If2bd0c3020d71bebc8947b758c22be40f607f9e6

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom