Implement --shm-path option for UST sessions (per-uid channels)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
shm-path: remove directory hierarchy on destroy

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
lttng-crash: support recursive traces

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Move file creation/unlink from liblttng-ust-ctl to consumerd

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Use run_as for unlink and recursive_rmdir

Enforce right restrictions to those of the user owning the session.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
ust consumer: unlink and rmdir on stream creation error

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>