docs: amend vmlinuz & initramfs naming convention

I was confused while reading the docs how this could work, since in at
least the Fedora/CentOS/RHEL distros, they're named e.g.
initramfs-`uname -r`-$checksum.

Closes: #529
Approved by: cgwalters

docs/manual/deployment.md

@@ -43,13 +43,14 @@ deployment.  For short, we will call this the "tree", to
 distinguish it from the concept of a deployment.
 
 First, the tree must include a kernel stored as
-`/boot/vmlinuz-$checksum`.  The checksum should be a SHA256 hash of
-the kernel contents; it must be pre-computed before storing the kernel
-in the repository.  Optionally, the tree can contain an initramfs,
-stored as `/boot/initramfs-$checksum`.  If this exists, the checksum
-must include both the kernel and initramfs contents.  OSTree will use
-this to determine which kernels are shared.  The rationale for this is
-to avoid computing checksums on the client by default.
+`vmlinuz(-.*)?-$checksum` in either `/boot` or `/usr/lib/ostree-boot`.
+The checksum should be a SHA256 hash of the kernel contents; it must be
+pre-computed before storing the kernel in the repository.  Optionally,
+the directory can also contain an initramfs, stored as
+`initramfs(-.*)?-$checksum`.  If this exists, the checksum must include
+both the kernel and initramfs contents.  OSTree will use this to
+determine which kernels are shared.  The rationale for this is to avoid
+computing checksums on the client by default.
 
 The deployment should not have a traditional UNIX `/etc`; instead, it
 should include `/usr/etc`.  This is the "default configuration".  When