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>

libconfuse.spec

@@ -7,7 +7,6 @@ Group:          System Environment/Libraries
 License:        ISC
 URL:            https://github.com/martinh/libconfuse
 Source0:	https://github.com/martinh/libconfuse/releases/download/v%{version}/confuse-%{version}.tar.gz
-BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  check-devel, pkgconfig
 BuildRequires:  perl-interpreter