Update submodules: parser (new commits)

parser:
    f21d923 Greg Holmes <greg@dmdirc.com>
            Fix compiler warnings.

            Gerrit: http://gerrit.dmdirc.com/3575

Change-Id: I45c3fd02e3ceea1de724f2a3f72b585d0f94d079

modules/parser

@@ -1 +1 @@
-Subproject commit 73aae226051350b780205ef80b3a457ccae72c2e
+Subproject commit f21d923df280b98fdf1f1b1a612823488cac88dc