debugger: use *running instead of ^running as running notification.

This is closer to internal gdb state. There are still a few workarounds
for gdb < 7.0 which probably should be dropped as BFD 2.18.50.20080226
yields "assertion fail elf32-i386.c:366" on stock Ubuntu 12.04 gcc,
so stock gdb 6.8 cannot be used with that compiler anyways.

Change-Id: I22c4e0ce91f634cc171d65f0ad07d68d679af10c
Reviewed-by: David Schulz <david.schulz@nokia.com>
Reviewed-by: hjk <qthjk@ovi.com>