r7669: removed ldap from our configure tests

r7669: removed ldap from our configure tests

This takes our link dependencies from this:

tridge@blu:~/samba/samba4/source$ ldd bin/ldbsearch
        libdl.so.2 => /lib/tls/libdl.so.2 (0xb7fc9000)
        libldap_r.so.2 => /usr/lib/libldap_r.so.2 (0xb7f92000)
        liblber.so.2 => /usr/local/lib/liblber.so.2 (0xb7f85000)
        libpam.so.0 => /lib/libpam.so.0 (0xb7f7d000)
        libc.so.6 => /lib/tls/libc.so.6 (0xb7e48000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0xb7fea000)
        libresolv.so.2 => /lib/tls/libresolv.so.2 (0xb7e36000)
        libcrypt.so.1 => /lib/tls/libcrypt.so.1 (0xb7e09000)
        libsasl2.so.2 => /usr/lib/libsasl2.so.2 (0xb7df3000)
        libgnutls.so.11 => /usr/lib/libgnutls.so.11 (0xb7d8c000)
        libpthread.so.0 => /lib/tls/libpthread.so.0 (0xb7d7d000)
        libtasn1.so.2 => /usr/lib/libtasn1.so.2 (0xb7d6d000)
        libgcrypt.so.11 => /usr/lib/libgcrypt.so.11 (0xb7d20000)
        libgpg-error.so.0 => /usr/lib/libgpg-error.so.0 (0xb7d1c000)
        libz.so.1 => /usr/lib/libz.so.1 (0xb7d09000)
        libnsl.so.1 => /lib/tls/libnsl.so.1 (0xb7cf5000)

to this:

tridge@blu:~/samba/samba4/source$ ldd bin/ldbsearch
        libdl.so.2 => /lib/tls/libdl.so.2 (0xb7fc9000)
        libpam.so.0 => /lib/libpam.so.0 (0xb7fc0000)
        libc.so.6 => /lib/tls/libc.so.6 (0xb7e8b000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0xb7fea000)

this finally gets rid of the implicit dependency on pthreads! Yay!