Readd get_openstack_logo_path

Change I594136a0ea66d61f60dafc6a853137470efc7d42 broke the API of this
package with renaming get_openstack_logo_path which broke a couple
of users, readd it.

Change-Id: Ia2f6760e0f6f53d94a8d3358d5c4e2fe0a2d7bf3

openstackdocstheme/paths.py

@@ -34,3 +34,9 @@ def get_theme_logo_path(theme='openstack'):
     """Return the directory containing theme logo for local builds."""
     args = ['theme', theme + '_pdf', 'logo-full.png']
     return os.path.join(get_pkg_path(), *args)
+
+
+# This function is for compatibility with previous releases.
+def get_openstack_logo_path():
+    """Return the directory containing openstack logo for local builds."""
+    return get_theme_logo_path('openstack')

releasenotes/notes/get_openstack_logo_path-6cdb6538bc5893c3.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fix API breakages in 1.26.0: Readd ``get_openstack_logo_path``,
+    add default parameter to ``get_pdf_theme_path``.