Office365OAuthService: Restore Accept header in user info request

In update of scribe version change: I68717ebb988 Accept header was
inadvertently removed. Restore the setting of Accept header to "*/*":

  request.addHeader("Accept", "*/*");

Bug: Issue https://github.com/davido/gerrit-oauth-provider/issues/144
Change-Id: I224f798c7fb37e24be7f4fecfc29e11932c51286
diff --git a/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java b/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java
index 0b22776..1ab9605 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java
@@ -80,6 +80,7 @@
     OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
     OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
+    request.addHeader("Accept", "*/*");
 
     JsonElement userJson = null;
     try (Response response = service.execute(request)) {