ignore build products in the submodules (ignore = dirty)

.gitmodules

@@ -1,30 +1,40 @@
 [submodule "external/tor"]
 	path = external/tor
 	url = https://git.torproject.org/git/tor.git
+	ignore = dirty
 [submodule "external/libevent"]
 	path = external/libevent
 	url = https://github.com/libevent/libevent.git
+	ignore = dirty
 [submodule "external/jtorctl"]
 	path = external/jtorctl
 	url = https://github.com/guardianproject/jtorctl
+	ignore = dirty
 [submodule "external/openssl"]
 	path = external/openssl
 	url = git://git.openssl.org/openssl
+	ignore = dirty
 [submodule "external/iptables"]
 	path = external/iptables
 	url = git://git.netfilter.org/iptables
+	ignore = dirty
 [submodule "external/superuser-commands"]
 	path = external/superuser-commands
 	url = https://github.com/dschuermann/superuser-commands.git
+	ignore = dirty
 [submodule "external/polipo"]
 	path = external/polipo
 	url = https://github.com/jech/polipo.git
+	ignore = dirty
 [submodule "external/badvpn"]
 	path = external/badvpn
 	url = https://github.com/guardianproject/badvpn.git
+	ignore = dirty
 [submodule "external/pluto"]
 	path = external/pluto
 	url = https://github.com/guardianproject/pluto.git
+	ignore = dirty
 [submodule "external/jsocks"]
 	path = external/jsocks
 	url = https://github.com/guardianproject/jsocks.git
+	ignore = dirty