shared: Fix use after free in queue_foreach

shared: Fix use after free in queue_foreach

Function passed to queue_foreach may free queue entry. Make loop safe
with that. Fix number of following valgrin reports.

Invalid read of size 8
   at 0x408EEC: queue_foreach (queue.c:181)
   by 0x409A0E: can_read_data (mgmt.c:286)
   by 0x40896C: read_callback (io-glib.c:164)
   by 0x4E7C3B5: g_main_context_dispatch (in
       /lib/x86_64-linux-gnu/libglib-2.0.so.0.3800.1)
   by 0x4E7C707: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.3800.1)
   by 0x4E7CB09: g_main_loop_run (in /lib/x86_64-linux-gnu/
       libglib-2.0.so.0.3800.1)
   by 0x40B5FC: tester_run (tester.c:784)
   by 0x4034F4: main (android-tester.c:2127)
 Address 0x59603a8 is 8 bytes inside a block of size 16 free'd
   at 0x4C2B60C: free (in /usr/lib/valgrind/
       vgpreload_memcheck-amd64-linux.so)
   by 0x40910D: queue_remove_all (queue.c:289)
   by 0x40A0BD: mgmt_unregister_all (mgmt.c:792)
   by 0x40A0F4: mgmt_unref (mgmt.c:499)
   by 0x40D814: index_removed_callback (android-tester.c:329)
   by 0x408EEB: queue_foreach (queue.c:184)
   by 0x409A0E: can_read_data (mgmt.c:286)
   by 0x40896C: read_callback (io-glib.c:164)
   by 0x4E7C3B5: g_main_context_dispatch (in /lib/x86_64-linux-gnu/
       libglib-2.0.so.0.3800.1)
   by 0x4E7C707: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.3800.1)
   by 0x4E7CB09: g_main_loop_run (in /lib/x86_64-linux-gnu/
       libglib-2.0.so.0.3800.1)
   by 0x40B5FC: tester_run (tester.c:784)