lib: Cleanup #include <>s

We previously severed the dependency between the shared library
and our internal code, but the library still included internal
headers even though they weren't used.

This broke my attempt to natively use C++ in some headers.

Drop the unused headers and clean up the `#include`s.

src/lib/rpmostree-db.c

@@ -19,13 +19,9 @@
  */
 
 #include "config.h"
-
 #include "string.h"
-
 #include "rpmostree-db.h"
-#include "rpmostree-rpm-util.h"
 #include "rpmostree-package-priv.h"
-#include "rpmostree-refsack.h"
 
 /**
  * SECTION:librpmostree-dbquery

src/lib/rpmostree-package-priv.h

@@ -23,12 +23,9 @@
 
 #include <ostree.h>
 #include "rpmostree-package.h"
-#include "rpmostree-refsack.h"
 
 G_BEGIN_DECLS
 
-RpmOstreePackage * _rpm_ostree_package_new (RpmOstreeRefSack *rsack, DnfPackage *hypkg);
-
 RpmOstreePackage * _rpm_ostree_package_new_from_variant (GVariant *gv_nevra);
 
 gboolean

src/lib/rpmostree-package.c

@@ -30,11 +30,13 @@
 
 #include "config.h"
 
-#include "rpmostree-shlib-ipc-private.h"
-#include "rpmostree-package-priv.h"
-
 #include <string.h>
 #include <stdlib.h>
+#include <libdnf/libdnf.h>
+#include "libglnx.h"
+
+#include "rpmostree-shlib-ipc-private.h"
+#include "rpmostree-package-priv.h"
 
 typedef GObjectClass RpmOstreePackageClass;