Comment 2 for bug 1041724

StacktraceTop:
 AptIntf::cancel (this=0x186f1a00) at apt-intf.cpp:136
 pk_transaction_cancel (transaction=transaction@entry=0x12ae250, context=context@entry=0x7f7918745580, params=<error reading variable: Unhandled dwarf expression opcode 0xfa>) at pk-transaction.c:3270
 pk_transaction_method_call (connection_=<optimized out>, sender=0x7f792c006e20 ":1.283", object_path=<optimized out>, interface_name=interface_name@entry=0x7f792c008250 "org.freedesktop.PackageKit.Transaction", method_name=method_name@entry=0x7f792c0083b0 "Cancel", parameters=0x12abe10, invocation=invocation@entry=0x7f7918745580, user_data=user_data@entry=0x12ae250) at pk-transaction.c:5954
 call_in_idle_cb (user_data=<optimized out>) at /build/buildd/glib2.0-2.33.10/./gio/gdbusconnection.c:4737
 g_main_dispatch (context=0x1255530) at /build/buildd/glib2.0-2.33.10/./glib/gmain.c:2707