set ABI to 2.slh.1.

* set ABI to 2.slh.1.
* import 3.17.2.
* update candidate patches for overlayfs
  - rcu: Provide counterpart to rcu_dereference() for non-RCU situations
  - overlayfs: barriers for opening upper-layer directory
  - ovl: fix check for cursor
  - overlayfs: fix lockdep misannotation
  - isofs_cmp(): we'll never see a dentry for . or ..
  - isofs: don't bother with ->d_op for normal case
NOT RELEASED YET

* NOT RELEASED YET
* set ABI to 2.slh.2.
* import 3.17.2-rc1.