Sample templates: Fix reference for intro_message

The intro_message string comes from sample.strings.intro, not
sample.intro.

Change-Id: I944114341557008afc009fec0bcf8cbec7eead63
diff --git a/common/build/templates/base/_MODULE_/src/template/res/values/base-strings.xml.ftl b/common/build/templates/base/_MODULE_/src/template/res/values/base-strings.xml.ftl
index 111d279..082c96f 100755
--- a/common/build/templates/base/_MODULE_/src/template/res/values/base-strings.xml.ftl
+++ b/common/build/templates/base/_MODULE_/src/template/res/values/base-strings.xml.ftl
@@ -2,7 +2,7 @@
     <string name="app_name">${sample.name}</string>
     <string name="intro_message">
         <![CDATA[
-        ${sample.intro}
+        ${sample.strings.intro}
         ]]>
     </string>
 </resources>
\ No newline at end of file