Bug 1710249 - Use SeaMonkey theme secure icons in cZ. r=frg

suite/chatzilla/jar.mn

@@ -109,8 +109,6 @@ chatzilla.jar:
 	skin/modern/chatzilla/images/multiline-expand.png   (xul/skin/images/multiline-expand.png)
 	skin/modern/chatzilla/images/multiline-contract.png (xul/skin/images/multiline-contract.png)
 	skin/modern/chatzilla/images/input-send.png         (xul/skin/images/input-send.png)
-	skin/modern/chatzilla/images/secure.png             (xul/skin/images/secure.png)
-	skin/modern/chatzilla/images/secure-broken.png      (xul/skin/images/secure-broken.png)
 	skin/modern/chatzilla/images/drop-indicator-bottom.png (xul/skin/images/drop-indicator-bottom.png)
 	skin/modern/chatzilla/images/logging-on.png      (xul/skin/images/logging-on.png)
 	skin/modern/chatzilla/images/logging-off.png     (xul/skin/images/logging-off.png)

suite/chatzilla/xul/skin/chatzilla.css

@@ -335,14 +335,6 @@ progressmeter[mode="undetermined"] {
     display: none;
 }
 
-#security-button[level="high"] {
-    list-style-image: url("chrome://chatzilla/skin/images/secure.png");
-}
-
-#security-button[level="broken"] {
-    list-style-image: url("chrome://chatzilla/skin/images/secure-broken.png");
-}
-
 #alert-status[alertstate="off"] {
     list-style-image: url("chrome://chatzilla/skin/images/spbubble-off.png");
 }