dirmngr: Let KS_SEARCH print all uid records for a key.

* dirmngr/ks-engine-ldap.c (ks_ldap_search): Use a loop to print all
  user-ids.

from March 2015 which introduced a regression from the
original keyserver helpers used by GnuPG versions < 2.1.0.

• Fixes-commit: 51341badb623927f2a358588c725a356fc77dbe7