android: set all zlib variables used by downstream packages

cmake/OpenCVFindLibsGrfmt.cmake

@@ -17,8 +17,10 @@ else()
     unset(_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES)
   endif()
   if(ZLIB_FOUND AND ANDROID)
-    if(ZLIB_LIBRARIES MATCHES "/usr/lib.*/libz.so$")
+    if(ZLIB_LIBRARY MATCHES "/usr/lib.*/libz.so$")
+      set(ZLIB_LIBRARY z)
       set(ZLIB_LIBRARIES z)
+      set(ZLIB_LIBRARY_RELEASE z)
     endif()
   endif()
 endif()