Switch to one process per web view model by default

data/org.gnome.epiphany.gschema.xml

@@ -67,7 +67,7 @@
                         <description>When this option is set to true, tabs will not start loading until the user switches to them, upon session restore.</description>
                 </key>
                 <key name="process-model" enum="org.gnome.Epiphany.EphyPrefsProcessModel">
-                        <default>'shared-secondary-process'</default>
+                        <default>'one-secondary-process-per-web-view'</default>
                         <summary>Process model</summary>
                         <description>This option allows to set the process model used. Use 'shared-secondary-process' to use a single web process shared by all the tabs and 'one-secondary-process-per-web-view' to use a different web process for each tab.</description>
                 </key>