phosphor: use standard proxy settings for phosphor-webui recipe

The current phosphor-webui compile stage needs to connect to the npm
registry. In build environments that use a proxy (specified by the
`http_proxy`) setting, this fails.

Although the current recipe provides proxy arguments through the
HTTP_PROXY environment variable, not many other download tools use this
(wget and curl do not).

Since the lower-case version needs to be set anyway (for wget), use that
instead of requiring both http_proxy and HTTP_PROXY.

Tested: phosphor-webui's do_compile target works with only
  http{,s}_proxy set

Fixes: https://github.com/openbmc/meta-phosphor/issues/14
Change-Id: I058134f458e95b37384f8615163a2c60f882918f
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/recipes-phosphor/webui/phosphor-webui_git.bb b/recipes-phosphor/webui/phosphor-webui_git.bb
index 89f4e24..5d36313 100644
--- a/recipes-phosphor/webui/phosphor-webui_git.bb
+++ b/recipes-phosphor/webui/phosphor-webui_git.bb
@@ -33,7 +33,7 @@
 do_compile () {
     cd ${S}
     rm -rf node_modules
-    npm --loglevel info --proxy=${HTTP_PROXY} --https-proxy=${HTTPS_PROXY} install
+    npm --loglevel info --proxy=${http_proxy} --https-proxy=${https_proxy} install
     npm run-script build
 }