SPEC: Remove unused build dependency on libwbclient

The string "wbclient" is not mentioned anywhere in
source code and there isn't any issue with building
freeipa packages without this package.

Reviewed-By: Sumit Bose <sbose@redhat.com>

BUILD.txt

@@ -16,7 +16,7 @@ or
 This is currently (2015-05-07):
 
 yum install rpm-build 389-ds-base-devel svrcore-devel policycoreutils \
-systemd-units samba-devel samba-python libwbclient-devel libtalloc-devel \
+systemd-units samba-devel samba-python libtalloc-devel \
 libtevent-devel nspr-devel nss-devel openssl-devel openldap-devel krb5-devel \
 krb5-workstation libuuid-devel libcurl-devel xmlrpc-c-devel popt-devel \
 autoconf automake m4 libtool gettext python-devel python-ldap \

freeipa.spec.in

@@ -48,7 +48,6 @@ BuildRequires:  policycoreutils >= 2.1.12-5
 BuildRequires:  systemd-units
 BuildRequires:  samba-devel >= %{samba_version}
 BuildRequires:  samba-python
-BuildRequires:  libwbclient-devel
 BuildRequires:  libtalloc-devel
 BuildRequires:  libtevent-devel
 %endif # ONLY_CLIENT