rpminfo: librpm 6 removal (#4787)

Author: remicollet

reference/rpminfo/constants.xml

@@ -1152,6 +1152,7 @@
    </term>
    <listitem>
     <simpara>
+      Deprecated, use <constant>RPMTAG_SHA1HEADER</constant> instead. Removed in librpm 6.
     </simpara>
    </listitem>
   </varlistentry>
@@ -1787,6 +1788,7 @@
    </term>
    <listitem>
     <simpara>
+      Deprecated, use <constant>RPMTAG_SIGMD5</constant> instead. Removed in librpm 6.
     </simpara>
    </listitem>
   </varlistentry>