http_client Add link to libcurl by using entity

docbook/entities.xml

@@ -103,4 +103,4 @@
 
 <!-- Often used 3rd party libraries  -->
 <!ENTITY openssl "<ulink url='https://www.openssl.org'>OpenSSL</ulink>">
-<!ENTITY curl "<ulink url='https://curl.haxx.se'>Curl</ulink>">
+<!ENTITY libcurl "<ulink url='https://curl.haxx.se'>libcurl</ulink>">

modules/http_client/doc/http_client_admin.xml

@@ -62,7 +62,7 @@
 			<listitem>
 			<para>
 			TLS - if you use TLS connections (https) the tls module should be
-			loaded first in order to initialize OpenSSL properly.
+			loaded first in order to initialize &openssl; properly.
 			</para>
 			</listitem>
 			</itemizedlist>
@@ -77,7 +77,7 @@
 			<itemizedlist>
 			<listitem>
 			<para>
-				<emphasis>libcurl</emphasis>.
+				<emphasis>&libcurl;</emphasis>.
 			</para>
 			</listitem>
 			</itemizedlist>