Twenty Seventeen: Make fixed navigation apply at correct height on front page, without header video or image

Props laurelfulford, littlebigthing.

Merges [39392] to the 4.7 branch.
Fixes #38927 for 4.7.

Built from https://develop.svn.wordpress.org/branches/4.7@39394


git-svn-id: http://core.svn.wordpress.org/branches/4.7@39334 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-content/themes/twentyseventeen/template-parts/header/header-image.php

@@ -11,9 +11,11 @@
 ?>
 <div class="custom-header">
 
+	<?php if ( has_custom_header() ) : ?>
 		<div class="custom-header-image">
 			<?php the_custom_header_markup(); ?>
 		</div>
+	<?php endif; ?>
 
 	<?php get_template_part( 'template-parts/header/site', 'branding' ); ?>
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-RC1-39391';
+$wp_version = '4.7-RC1-39394';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.