fetch-develop-deps: avoid breaking js-sdk

do `npm i` in react-sdk *before* symlinking js-sdk, to avoid moving a load of
deps from js-sdk to react-sdk and hence breaking the build.

scripts/fetch-develop.deps.sh

@@ -49,42 +49,47 @@ function dodep() {
         [ "$curbranch" != 'develop' ] && clone $org $repo develop
     } || return $?
 
-    (
-        cd $repo
-        echo "$repo set to branch "`git rev-parse --abbrev-ref HEAD`
-    )
+    echo "$repo set to branch "`git -C "$repo" rev-parse --abbrev-ref HEAD`
 
     mkdir -p node_modules
     rm -r "node_modules/$repo" 2>/dev/null || true
     ln -sv "../$repo" node_modules/
+
+    (
+        cd $repo
+        npm install
+    )
 }
 
+##############################
+
 echo -en 'travis_fold:start:matrix-js-sdk\r'
 echo 'Setting up matrix-js-sdk'
 
 dodep matrix-org matrix-js-sdk
-(
-    cd node_modules/matrix-js-sdk
-    npm install
-)
 
 echo -en 'travis_fold:end:matrix-js-sdk\r'
 
+##############################
+
 echo -en 'travis_fold:start:matrix-react-sdk\r'
 echo 'Setting up matrix-react-sdk'
 
 dodep matrix-org matrix-react-sdk
 
-mkdir -p node_modules/matrix-react-sdk/node_modules
+# replace the version of js-sdk that got pulled into react-sdk with a symlink
+# to our version. Make sure to do this *after* doing 'npm i' in react-sdk,
+# otherwise npm helpfully moves another-json from matrix-js-sdk/node_modules
+# into matrix-react-sdk/node_modules.
+#
+# (note this matches the instructions in the README.)
+rm -r node_modules/matrix-react-sdk/node_modules/matrix-js-sdk
 ln -s ../../matrix-js-sdk node_modules/matrix-react-sdk/node_modules/
 
-(
-    cd node_modules/matrix-react-sdk
-    npm install
-)
-
 echo -en 'travis_fold:end:matrix-react-sdk\r'
 
+##############################
+
 # Link the reskindex binary in place: if we used npm link,
 # npm would do this for us, but we don't because we'd have
 # to define the npm prefix somewhere so it could put the