Network-Manager applet crashes when ModemManager restarts

"sudo service ModemManager restart" results in this crash:

#0 0x00007ffff4d4b267 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:55
#1 0x00007ffff4d4ceca in __GI_abort () at abort.c:89
#2 0x00007ffff536db55 in g_assertion_message () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3 0x00007ffff536dbea in g_assertion_message_expr () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4 0x000000000043215f in get_icon (device=0x8f23a0, state=NM_DEVICE_STATE_PREPARE, connection=0x7fffd801d650, out_pixbuf=0x7fffffffdcc8, out_indicator_icon=0x7fffffffdcd8, tip=0x7fffffffdcd0,
    applet=0x794780) at applet-device-broadband.c:644
#5 0x000000000041be32 in applet_get_device_icon_for_state (out_tip=<optimized out>, out_indicator_icon=<optimized out>, out_pixbuf=<optimized out>, applet=<optimized out>) at applet.c:3258
#6 applet_update_icon (user_data=0x794780) at applet.c:3365
#7 0x00007ffff5347b4d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8 0x00007ffff5347f20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9 0x00007ffff5348242 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00000000004132ec in main (argc=1, argv=0x7fffffffdf58) at main.c:106

This is exactly the same place the patch for LP1418260 tries to fix. Apparently that patch is incomplete (or incorrect). With the attached patch the crash disappears.