Travis: do non-threadsafe builds

When flipping the default to threadsafe, we never made sure that the
tests were building non-threadsafe variants. Specify which thead-safety
we want for each.

.travis.yml

@@ -17,7 +17,7 @@ env:
   - secure: "YnhS+8n6B+uoyaYfaJ3Lei7cSJqHDPiKJCKFIF2c87YDfmCvAJke8QtE7IzjYDs7UFkTCM4ox+ph2bERUrxZbSCyEkHdjIZpKuMJfYWja/jgMqTMxdyOH9y8JLFbZsSXDIXDwqBlC6vVyl1fP90M35wuWcNTs6tctfVWVofEFbs="
  matrix:
   - OPTIONS="-DTHREADSAFE=ON -DCMAKE_BUILD_TYPE=Release"
-  - OPTIONS="-DBUILD_CLAR=ON -DBUILD_EXAMPLES=ON"
+  - OPTIONS="-DTHREADSAFE=OFF -DBUILD_EXAMPLES=ON"
 
 matrix:
  fast_finish: true