Add hint about the optional LDAP modules listed in "suggest" (#1490183)

INSTALL

@@ -49,6 +49,9 @@ INSTALLATION
 2. Install dependencies using composer:
    - get composer from https://getcomposer.org/download/
    - rename the composer.json-dist file into composer.json
+   - if you want to use LDAP address books, enable the LDAP libraries in your
+     composer.json file by moving the items from "suggest" to the "require"
+     section (remove the explanation texts after the version!).
    - run `php composer.phar install --no-dev`
 3. Make sure that the following directories (and the files within)
    are writable by the webserver

composer.json-dist

@@ -44,7 +44,7 @@
         "phpunit/phpunit": "*"
     },
     "suggest": {
-        "pear-pear.php.net/net_ldap2": "Version >=2.0.12 required for connecting to LDAP address books",
+        "pear-pear.php.net/net_ldap2": ">=2.0.12 required for connecting to LDAP address books",
         "kolab/Net_LDAP3": "dev-master required for connecting to LDAP address books"
     },
     "minimum-stability": "dev"