Remove BuildRoot definition

None of currently supported distributions need that.
It was needed last for EL5 which is EOL now

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

ruby-augeas.spec

@@ -7,7 +7,6 @@ Group:          Development/Languages
 License:        LGPLv2+
 URL:            http://augeas.net
 Source0:        http://download.augeas.net/ruby/ruby-augeas-%{version}.tgz
-BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  ruby rubygem(rake) rubygem(test-unit)
 BuildRequires:  ruby rubygem(rdoc)