smb: client: fix oops due to uninitialised var in smb2_unlink()

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix oops due to uninitialised var in smb2_unlink()

If SMB2_open_init() or SMB2_close_init() fails (e.g. reconnect), the iovs set @rqst will be left uninitialised, hence calling SMB2_open_free(), SMB2_close_free() or smb2_set_related() on them will oops.

Fix this by initialising @close_iov and @open_iov before setting them in @rqst.