Cannot remove breakpoints after stopping debugger

Note: Might be related to actually not fully supporting using mixed debugging for LLDB.

Steps to reproduce:

• configure a kit using LLDB engine (I've used Qt5.1.0, clang, lldb)
• create a simple Qt Quick 2 application
• set breakpoints in C++ part (I've set some into main.cpp and mainwindow.cpp)
• start debugging, wait until one of the breakpoints got hit, stop debugging
• try to remove a breakpoint

Current behaviour:

• breakpoints stay until closing Qt Creator

Expected behaviour:

• breakpoints can be removed as usual