Use debhelper 11 features instead of dh-exec

Since compat level 11, man pages installed by the upstream build system
can be listed in d/*.manpages and will automatically be excluded under
the nodoc build-profile.

debian/ostree.install

@@ -1,8 +1,5 @@
-#!/usr/bin/dh-exec
-
 etc/ostree
 usr/bin/ostree
 usr/bin/rofiles-fuse
 usr/share/bash-completion/completions/ostree
-usr/share/man <!nodoc>
 usr/share/ostree/trusted.gpg.d

debian/ostree.manpages

@@ -0,0 +1 @@
+usr/share/man/man?/*