Set minimum OS X version to 10.5.x in DevicePermissionPrompt.xib.

This resolves a number of compile-time warnings about features that
are not available in versions prior to 10.5.

BUG=427654

Review URL: https://codereview.chromium.org/678763008

Cr-Commit-Position: refs/heads/master@{#301584}

chrome/app/nibs/DevicePermissionsPrompt.xib

 <?xml version="1.0" encoding="UTF-8"?>
 <archive type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="8.00">
 	<data>
-		<int key="IBDocument.SystemTarget">0</int>
+		<int key="IBDocument.SystemTarget">1050</int>
 		<string key="IBDocument.SystemVersion">12F45</string>
 		<string key="IBDocument.InterfaceBuilderVersion">3084</string>
 		<string key="IBDocument.AppKitVersion">1187.40</string>
@@ -794,7 +794,7 @@ ARcABAAAAAEAAAACARwAAwAAAAEAAQAAAVIAAwAAAAEAAQAAAVMAAwAAAAIAAQABAAAAAA</bytes>
 		<string key="IBDocument.TargetRuntimeIdentifier">IBCocoaFramework</string>
 		<object class="NSMutableDictionary" key="IBDocument.PluginDeclaredDependencies">
 			<string key="NS.key.0">com.apple.InterfaceBuilder.CocoaPlugin.macosx</string>
-			<real value="0.0" key="NS.object.0"/>
+			<real value="1050" key="NS.object.0"/>
 		</object>
 		<object class="NSMutableDictionary" key="IBDocument.PluginDeclaredDependencyDefaults">
 			<string key="NS.key.0">com.apple.InterfaceBuilder.CocoaPlugin.macosx</string>