Use Rakes fileutils for command execution

.gitignore

@@ -25,4 +25,6 @@
 /config/config.rb
 /vendor/
 /.bundle/
+
 /debug/PackageKit/PackageKit/
+/debug/PackageKit/package/

debug/PackageKit/PackageKit.rb

@@ -9,8 +9,9 @@
 # For the script to work PackageKit source should be in the ./PackageKit
 # directory alongside this script.
 
-require 'fileutils'
+require 'rake/file_utils'
 require 'pathname'
+require 'rake'
 require 'open3'
 
 CWD = Pathname.new Dir.pwd
@@ -28,7 +29,7 @@ version = `git -C #{SOURCE} describe --tags --abbrev=0`
   .delete_prefix('PACKAGEKIT_')
   .gsub('_', '.')
 
-exec_result = system 'meson',
+sh 'meson',
   '--buildtype=debug',
   '--prefix=/usr',
   '--libdir=/usr/lib64',
@@ -43,10 +44,9 @@ exec_result = system 'meson',
   '-Ddaemon_tests=true',
   TMP.to_s,
   SOURCE.to_s
-raise 'Meson build failed' unless exec_result
 
-exec_result = system({'DESTDIR' => DESTINATION.to_s}, 'ninja', '-C', TMP.to_s, 'install')
-raise 'Ninja installation failed' unless exec_result
+sh({ 'DESTDIR' => DESTINATION.to_s },
+  'ninja', '-C', TMP.to_s, 'install')
 
 actual_mandir = DESTINATION + 'usr/share/man/man1'
 mandir = DESTINATION + 'usr/man/man1'