Fixes a build failure introduced with newer versions of Boost.
* gnu/packages/patches/ceph-fix-for-newer-boost.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/storage.scm (ceph): Update to 17.2.7. Use the patch.
Co-authored-by: Ludovic Courtès <ludo@gnu.org>
Change-Id: I00f2d369d7a86926b00c680d5ab0fe8044ca9065