drop unneeded code

ref #8934 

Following diff adds the icon-confirm button, but this just works on Chromium, Firefox and IE9. The fix for IE10 and IE11 is to apply the same fix as for IE9, but there are no easy ways to detect (except JS magic) IE10 and IE11. IE8 is broken.

@jancborchardt we need to fix the button CSS and header CSS. It's quite unstable ...

```
diff --git a/apps/files_sharing/css/public.css b/apps/files_sharing/css/public.css
index ddd9d10..1efd551 100644
--- a/apps/files_sharing/css/public.css
+++ b/apps/files_sharing/css/public.css
@@ -94,17 +94,32 @@ thead {
 	height: 14px;
 	line-height: 16px;
 	padding: 6px;
+	border-top-right-radius: 0;
+	border-bottom-right-radius: 0;
 }
 
 #save button {
 	margin: 0 5px;
 	height: 28px;
-	padding-bottom: 4px;
+	padding-bottom: 3px;
 	line-height: 14px;
 }
 
+#save .save-form button {
+	margin-left: -3px;
+	padding-bottom: 8px;
+}
+
 #save .save-form [type="submit"] {
-	margin: 0 5px;
+	margin: 0 5px 0 -4px;
 	height: 28px;
-	padding-bottom: 4px;
+	padding: 8px;
+	border-top-left-radius: 0;
+	border-bottom-left-radius: 0;
+	line-height: 10px;
+}
+
+/* this also should be applied to ie10 and ie11 but there is no CSS class for this */
+.ie9 #save .save-form [type="submit"] {
+	padding-bottom: 5px;
 }
diff --git a/apps/files_sharing/templates/public.php b/apps/files_sharing/templates/public.php
index 65e620a..f8a15f5 100644
--- a/apps/files_sharing/templates/public.php
+++ b/apps/files_sharing/templates/public.php
@@ -20,7 +20,7 @@
 					<button><?php p($l->t('Add to your ownCloud')) ?></button>
 					<form class="save-form hidden" action="#">
 						<input type="text" id="remote_address" placeholder="<?php p($l->t('example.com/owncloud')) ?>"/>
-						<input type="submit" value="<?php p($l->t('Save')) ?>"/>
+						<input type="submit" value="" class="svg icon-confirm" />
 					</form>
 				</span>
 				<a href="<?php p($_['downloadURL']); ?>" id="download" class="button">
```