npm install fails, dependency @polymer/iron-flex-layout@gloo not found

### Description

When trying to install the app-layout package with NPM it fails with the following error:



```

$ npm install @polymer/app-layout --save 

npm ERR! code ETARGET

npm ERR! notarget No matching version found for @polymer/iron-flex-layout@gloo

npm ERR! notarget In most cases you or one of your dependencies are requesting

npm ERR! notarget a package version that doesn't exist.

npm ERR! notarget 

npm ERR! notarget It was specified as a dependency of '@polymer/app-layout'

npm ERR! notarget 



npm ERR! A complete log of this run can be found in:

npm ERR!     /home/noah/.npm/_logs/2017-07-13T03_29_31_549Z-debug.log

```



[Link to complete debug.log specified in above error message](https://gist.github.com/Noah-Huppert/824d81914ddb3b188196675a199305a5)



It looks like the app-layout package on NPM is specifying the iron-flex-layout package with the version tag `gloo`. This seems very odd and not like any expected behavior. 



I looked in the app-layout and iron-flex-layout repositories and I couldn't find any dependencies with the tag `gloo`.



### Expected outcome

The package installs successfully with NPM.



### Actual outcome

The package install fails with an very odd dependency error. Which insists that the package iron-flex-layout is required as a dependency with the version tag `gloo`.



### Live Demo

Unfortunately I can not provide a live demo as this is a NPM install issue. Hopefully with the provided system info and the steps below the issue can be reproduced.



System info:

```

$ uname -a

Linux Ikebukuro 4.11.6-1-ARCH #1 SMP PREEMPT Sat Jun 17 08:19:42 CEST 2017 x86_64 GNU/Linux



$ cat /etc/*-release

NAME="Arch Linux"

PRETTY_NAME="Arch Linux"

ID=arch

ID_LIKE=archlinux

ANSI_COLOR="0;36"

HOME_URL="https://www.archlinux.org/"

SUPPORT_URL="https://bbs.archlinux.org/"

BUG_REPORT_URL="https://bugs.archlinux.org/"



$ npm --version

5.2.0

```



### Steps to reproduce

1. Create an empty directory and cd into it

2. Run `npm init` and fill out fields appropriately

3. Install Polymer first, `npm install @polymer/polymer --save`

5. Next attempt to install app-layout, `npm install @polymer/app-layout --save`

    - I have determined that this issue occurs with and without the save flag

5. Install fails with a dependency error



### Browsers Affected

None, developer side install issue

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