Remove superfluous build requirement to pkg-config from the main package.

OBS-URL: https://build.opensuse.org/package/show/network:samba:STABLE/ldb?expand=0&rev=45

ldb.spec

@@ -60,11 +60,6 @@ Ldb is an LDAP-like embedded database.
 %package -n %{libldb_name}
 Summary:        An LDAP-like embedded database
 Group:          System/Libraries
-%if 0%{?suse_version} > 1020
-BuildRequires:  pkg-config
-%else
-BuildRequires:  pkgconfig
-%endif
 PreReq:         /sbin/ldconfig
 
 %description -n %{libldb_name}