gitmodules: Remove riot-* from submodule list; minor cleanup.

.gitmodules

@@ -1,22 +1,10 @@
+[submodule "boost"]
+	path = deps/boost
+	url = https://github.com/boostorg/boost.git
 [submodule "rocksdb"]
 	path = deps/rocksdb
 	url = https://github.com/facebook/rocksdb.git
 [submodule "gecko-dev"]
 	path = deps/gecko-dev
 	url = https://github.com/mozilla/gecko-dev.git
 	branch = esr45
-[submodule "boost"]
-	path = deps/boost
-	url = https://github.com/boostorg/boost.git
-[submodule "deps/riot-web"]
-	path = deps/riot-web
-	url = https://github.com/vector-im/riot-web.git
-	branch = develop
-[submodule "deps/matrix-js-sdk"]
-	path = deps/matrix-js-sdk
-	url = https://github.com/matrix-org/matrix-js-sdk.git
-	branch = develop
-[submodule "deps/matrix-react-sdk"]
-	path = deps/matrix-react-sdk
-	url = https://github.com/matrix-org/matrix-react-sdk.git
-	branch = develop