[O] issue with deadline and schedule on same line

[Divan Santana]

Hi Org users

Quick one. Having an issue when trying to fire up `org-agenda`.

It errors with:

```
org-agenda-get-day-entries: Wrong type argument: number-or-marker-p, 
"<2016-12-20 Tue +1m>"
```

That's when one tries to read this file in:

```
* Tasks
** TODO [#B] Do budget for next Month - 20th        :money:admin:2pomodoros:
DEADLINE: <2016-12-20 Tue +1m> SCHEDULED: <2016-12-20 Tue +1m>

```

Is this expected? Or am I doing something wrong?

If I have just DEADLINE or SCHEDULED entry then `org-agenda` fires up
without an issue.

Any ideas?

#### System Info :computer:
- OS: gnu/linux
- Emacs: 25.1.1
- Spacemacs: 0.200.5
- Spacemacs branch: master (rev. 664ba6ab)
- Graphic display: t
- Distribution: spacemacs
- Editing style: vim
- Completion: helm
- Layers:
```elisp
((auto-completion :variables auto-completion-enable-snippets-in-popup t 
auto-completion-private-snippets-directory
                  (list "~/.spacemacs.d/snippets" 
"~/.spacemacs.d/private/snippets"))
 better-defaults command-log colors csv dash docker deft
 (elfeed :variables rmh-elfeed-org-files
         (list "~/.spacemacs.d/elfeed.org" 
"~/.spacemacs.d/private/elfeed-private.org")
         elfeed-use-curl t url-queue-timeout 60)
 emacs-lisp erc finance git github html
 (markdown :variables markdown-live-preview-engine 'vmd)
 (mu4e :variables mu4e-installation-path "/usr/share/emacs/site-lisp")
 nginx
 (org :variables org-enable-github-support t)
 pandoc pass pdf-tools php puppet python ranger ruby search-engine
 (shell :variables shell-default-position 'full shell-default-shell 'multi-term)
 shell-scripts slack
 (spell-checking :variables spell-checking-enable-by-default nil)
 sql syntax-checking systemd themes-megapack twitter vagrant windows-scripts 
xkcd yaml)
```
- System configuration features: XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND 
GPM DBUS GCONF GSETTINGS NOTIFY ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT 
ZLIB TOOLKIT_SCROLL_BARS GTK3 X11