ci: Disable shallow submodules since they lead to errors on travis.

It seems that for shallow submodules travis sometimes does not find
the referenced remote commit

.gitmodules

@@ -1,9 +1,7 @@
 [submodule "deps/mdnsd"]
 	path = deps/mdnsd
 	url = https://github.com/Pro/mdnsd.git
-	shallow = true
 [submodule "deps/ua-nodeset"]
 	path = deps/ua-nodeset
 	url = https://github.com/OPCFoundation/UA-Nodeset
 	branch = v1.04
-	shallow = true

deps/mdnsd

@@ -1 +1 @@
-Subproject commit f7f0dd543f12fa7bbf2b667cceb287b9c8184b7d
+Subproject commit 5af316c4b79460c0c1b6c2a674a37e28a85441a3