Fix fakeldap search_s documentation
Fix fakeldap search_s documentation

FakeLdap's search_s documentation said it only supported base and
subtree, but it also supports onelevel.

Change-Id: I7536855d5a94a5d570e993be1a1e3da92ddd9e0f

nuxeh/keystone,rajalokan/keystone,takeshineshiro/keystone,jumpstarter-io/keystone,ilay09/keystone,dims/keystone,vivekdhayaal/keystone,mahak/keystone,UTSA-ICS/keystone-kerberos,maestro-hybrid-cloud/keystone,jamielennox/keystone,UTSA-ICS/keystone-kerberos,promptworks/keystone,promptworks/keystone,rushiagr/keystone,klmitch/keystone,klmitch/keystone,vivekdhayaal/keystone,promptworks/keystone,maestro-hybrid-cloud/keystone,vivekdhayaal/keystone,jumpstarter-io/keystone,MaheshIBM/keystone,ilay09/keystone,himanshu-setia/keystone,himanshu-setia/keystone,jamielennox/keystone,ajayaa/keystone,dstanek/keystone,ajayaa/keystone,rajalokan/keystone,jonnary/keystone,openstack/keystone,ging/keystone,ilay09/keystone,roopali8/keystone,takeshineshiro/keystone,blueboxgroup/keystone,mahak/keystone,dstanek/keystone,nuxeh/keystone,rushiagr/keystone,MaheshIBM/keystone,mahak/keystone,jumpstarter-io/keystone,openstack/keystone,rajalokan/keystone,dims/keystone,ging/keystone,idjaw/keystone,dstanek/keystone,rushiagr/keystone,nuxeh/keystone,cernops/keystone,blueboxgroup/keystone,jonnary/keystone,cernops/keystone,roopali8/keystone,openstack/keystone,idjaw/keystone