Linux: Correct the path to gnome-default-applications.xml.

BUG=171301

Review URL: https://codereview.chromium.org/1111113002

Cr-Commit-Position: refs/heads/master@{#327445}

chrome/installer/linux/common/default-app.template

@@ -2,7 +2,8 @@
 <!DOCTYPE default-apps SYSTEM "gnome-da-list.dtd">
 <!-- This file should be put in /usr/share/gnome-control-center/default-apps,
      or, if that directory does not exist, its web-browser tag patched into
-     /usr/share/gnome-control-center/gnome-default-applications.xml -->
+     /usr/share/gnome-control-center/default-apps/gnome-default-applications.xml
+     -->
 <default-apps>
   <web-browsers>
     <web-browser>

chrome/installer/linux/common/postinst.include

@@ -63,11 +63,11 @@ insert_after_first_match() {
     }" "$1"
 }
 
-# If /usr/share/gnome-control-center/gnome-default-applications.xml exists, it
-# may need to be updated to add ourselves to the default applications list. If
-# we find the file and it does not seem to contain our patch already (the patch
-# is safe to leave even after uninstall), update it.
-GNOME_DFL_APPS=/usr/share/gnome-control-center/gnome-default-applications.xml
+# If /usr/share/gnome-control-center/default-apps/gnome-default-applications.xml
+# exists, it may need to be updated to add ourselves to the default applications
+# list. If we find the file and it does not seem to contain our patch already
+# (the patch is safe to leave even after uninstall), update it.
+GNOME_DFL_APPS=/usr/share/gnome-control-center/default-apps/gnome-default-applications.xml
 if [ -f "$GNOME_DFL_APPS" ]; then
 # Conditionally insert the contents of the file "default-app-block" after the
 # first "<web-browsers>" line we find in gnome-default-applications.xml