Fix DllCanUnloadNow behavior
* src/gpgoladdin.cpp (DllCanUnloadNow): Only return OK if the addin is not connected.
The addinlocks variable made no sense to use for this. Now we just
check if we are connected or not. When we are not connected no
callbacks are used and it is safe to unload gpgol. Otherwise
we can't be safely unloaded.
- GnuPG-Bug-Id: T1837