Linux: fix calls to "which" in maintainer scripts to be non-fatal

chrome/installer/linux/common/prerm.include

Index: chrome/installer/linux/common/prerm.include
diff --git a/chrome/installer/linux/common/prerm.include b/chrome/installer/linux/common/prerm.include
index 3e6f9d7b554e9cdfc5550772c8d46a4d241e3ad6..e70dfdf38fcbb93b0f160e52be1952034111c10d 100644
--- a/chrome/installer/linux/common/prerm.include
+++ b/chrome/installer/linux/common/prerm.include
@@ -1,5 +1,5 @@
 # Remove icons from the system icons
-XDG_ICON_RESOURCE="`which xdg-icon-resource 2> /dev/null`"
+XDG_ICON_RESOURCE="`which xdg-icon-resource 2> /dev/null || true`"
 if [ ! -x "$XDG_ICON_RESOURCE" ]; then
   echo "Error: Could not find xdg-icon-resource" >&2
   exit 1
@@ -10,8 +10,8 @@ for icon in "@@INSTALLDIR@@/product_logo_"*.png; do
 done
 
 # Remove the entry from the system menu
-XDG_DESKTOP_MENU="`which xdg-desktop-menu 2> /dev/null`"
-UPDATE_MENUS="`which update-menus 2> /dev/null`"
+XDG_DESKTOP_MENU="`which xdg-desktop-menu 2> /dev/null || true`"
+UPDATE_MENUS="`which update-menus 2> /dev/null || true`"
 if [ ! -x "$XDG_DESKTOP_MENU" ]; then
   echo "Error: Could not find xdg-desktop-menu" >&2
   exit 1