Recreate code_cache directory after deleting account
We already recreate the cache directory after deleting the account because some OpenGL drivers expect it to exist. Apparently we should do the same for the code_cache directory. This comes from a Sony Xperia Z3 Compact (Android 6.0.1):
08-30 00:33:24.161 E/libEGL (14478): error creating cache file /data/user/0/org.briarproject.briar.android.debug/code_cache/com.android.opengl.shaders_cache: No such file or directory (2)