Static deltas support

https://bugzilla.gnome.org/show_bug.cgi?id=721799
test-rollsum: Process all input, print more statistics

Copying the bup code, we need to loop over all chunks even after
hitting the rollsum returning 0.

Also print more statistics.
ostree-repo-pull: Remove wrong assert condition

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fix a used before initialization warning

src/libostree/ostree-repo-pull.c:1676:22: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized]

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
use gs_unref_object not gs_free on a GFile

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
fix --help for static-delta

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
test: Fix invocation of static-delta

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>