ONOS-4359: continued work on theming UI
- updated xClose glyph
- replace double with single quotes in glyphData.js
- fixed close button on AppView details panel

Change-Id: I1e9139d096bdb4836710f019b5ee4e1c3c6e69e5
(cherry picked from commit 1fc873b)
diff --git a/web/gui/src/main/webapp/app/fw/svg/icon-theme.css b/web/gui/src/main/webapp/app/fw/svg/icon-theme.css
index bb63531..74e1654 100644
--- a/web/gui/src/main/webapp/app/fw/svg/icon-theme.css
+++ b/web/gui/src/main/webapp/app/fw/svg/icon-theme.css
@@ -19,11 +19,11 @@
  */
 
 .light div.close-btn svg.embeddedIcon g.icon .glyph {
-    fill: #9fa296;
+    fill: #333333;
 }
 .dark div.close-btn svg.embeddedIcon g.icon .glyph {
     /* TODO: dark theme */
-    fill: #9fa296;
+    fill: #333333;
 }