Debugger: Report LLDB error if bridge could not attach to process

Change-Id: Id54c0e21d7d803505b45f92ecf0a208771d10b81
Reviewed-by: David Schulz <david.schulz@qt.io>

share/qtcreator/debugger/lldbbridge.py

@@ -943,6 +943,7 @@ class Dumper(DumperBase):
             attach_info = lldb.SBAttachInfo(self.attachPid_)
             self.process = self.target.Attach(attach_info, error)
             if not error.Success():
+                self.report(self.describeError(error))
                 self.reportState('enginerunfailed')
             else:
                 self.report('pid="%s"' % self.process.GetProcessID())