koji-osbuild.spec: don't generate from .in file

Remove koji-osbuild.spec.in and the bits in meson.build that generate
the final spec file out of it. Pull in the changelog from how Ondřej
Budai does it in osbuild-composer, because it's adorable.

When releasing, the version now has to be bumped in the spec file.

This is to make it consistent with other osbuild projects, and to
simplify reverse dependency testing.

koji-osbuild.spec

@@ -1,8 +1,7 @@
-%global         commit @commit@
 %global         forgeurl https://github.com/osbuild/koji-osbuild
 
 Name:           koji-osbuild
-Version:        @version@
+Version:        3
 Release:        0%{?dist}
 Summary:        Koji integration for osbuild composer
 
@@ -152,5 +151,8 @@ Integration tests for koji-osbuild. To be run on a dedicated system.
 
 
 %changelog
-* @longdate@ osbuild <osbuilders@osbuild.org> - @version@-@reltag@
-- build from git sources.
+# the changelog is distribution-specific, therefore there's just one entry
+# to make rpmlint happy.
+
+* Tue Aug 25 2020 Image Builder team <osbuilders@osbuild.org> - 0-1
+- On this day, this project was born.

meson.build

@@ -1,4 +1,4 @@
-project('koji-osbuild', license: 'ASL 2.0', version: '3')
+project('koji-osbuild', license: 'ASL 2.0')
 
 srcdir = meson.source_root()
 
@@ -16,33 +16,12 @@ install_data(
 )
 
 git = find_program('git')
-
-subs = configuration_data()
-subs.set('version', meson.project_version())
-
-longdate = run_command('date', '+%a %b %d %Y').stdout().strip()
-subs.set('longdate', longdate)
-
-gitres = run_command(git, ['--git-dir=@0@/.git'.format(srcdir),
-                           'rev-parse',
-                           '--short=7',
-                           'HEAD'])
-
-if gitres.returncode() == 0
-  commit = gitres.stdout().strip()
-  subs.set('commit', commit)
-
-  gitrev = gitres.stdout().strip()
-  gitdate = run_command('date', '+%Y%m%d').stdout().strip()
-  # YYYYMMDD<scm><revision>
-  subs.set('reltag', '@0@git@1@'.format(gitdate, gitrev))
-endif
-
-spec_file = configure_file(
-  input: 'koji-osbuild.spec.in',
-  output: 'koji-osbuild.spec',
-  configuration: subs
+gitres = run_command(
+  git,
+  ['--git-dir=@0@/.git'.format(srcdir), 'rev-parse', 'HEAD'],
+  check=True
 )
+commit = gitres.stdout().strip()
 
 archive_name = meson.project_name() + '-' + gitrev
 full_archive_name = archive_name + '.tar.gz'
@@ -79,7 +58,8 @@ srpm_target = custom_target(
     rpmbuild, '-bs',
     spec_file,
     '--define', '_sourcedir ' + meson.build_root(),
-    '--define', '_topdir ' + rpmdirs_target.full_path()
+    '--define', '_topdir ' + rpmdirs_target.full_path(),
+    '--define', 'commit ' + commit
   ],
   output: 'srpms',
   depends: [archive]
@@ -91,15 +71,14 @@ rpm_target = custom_target(
     rpmbuild, '-ba',
     spec_file,
     '--define', '_sourcedir ' + meson.build_root(),
-    '--define', '_topdir ' + rpmdirs_target.full_path()
+    '--define', '_topdir ' + rpmdirs_target.full_path(),
+    '--define', 'commit ' + commit
   ],
   output: 'rpms',
   depends: [archive]
 )
 
 msg = ['',
-  'version:               @0@'.format(meson.project_version()),
-  '',
   'hub plugins path:      @0@'.format(hub_plugins_path),
   'builder plugins path:  @0@'.format(builder_plugins_path),
   '',