Reenabled adding native app glue for Android samples.

cmake/OpenCVDetectAndroidSDK.cmake

@@ -283,7 +283,7 @@ macro(add_android_project target path)
         ocv_include_modules_recurse(${android_proj_NATIVE_DEPS})
         ocv_include_directories("${path}/jni")
 
-        if (NATIVE_APP_GLUE AND 0)
+        if(NATIVE_APP_GLUE)
           include_directories(${ANDROID_NDK}/sources/android/native_app_glue)
           list(APPEND android_proj_jni_files ${ANDROID_NDK}/sources/android/native_app_glue/android_native_app_glue.c)
           ocv_warnings_disable(CMAKE_C_FLAGS -Wstrict-prototypes -Wunused-parameter -Wmissing-prototypes)