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>

libmpcdec.spec

@@ -8,7 +8,6 @@ License: BSD
 Group: 	 System Environment/Libraries
 URL: 	 http://www.musepack.net/
 Source0: http://files.musepack.net/source/libmpcdec-%{version}.tar.bz2
-BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 %description
 Musepack is an audio compression format with a strong emphasis on high quality.