Disable pindrop_demo build in Zooshi.
Disable pindrop_demo build in Zooshi.

Tested:
Built Zooshi for Linux and verified the pindrop_demo is no longer
being built.

Change-Id: I36131275279deb4f6cb61a0f054831110a22f0a8

google/zooshi,google/zooshi,google/zooshi,google/zooshi,google/zooshi