try to fix Travis build

Author: jmckenna

mapcache.xml.sample

@@ -875,9 +875,18 @@
 	 <dimension type="regex" name="MAPFILE" default="/path/to/mapfile.map">
 		 <regex>^(?!.*\.\.)[a-zA-Z0-9\./]*\.map$</regex>
 	 </dimension>
+	 
+         <!-- intervals dimension
+            the syntax is the same as common-ows, i.e. a comma separated list of "min/max/resolution" entries.
+            eg: 
+               * 0/5000/1000 allows the values 0,1000,2000,3000,4000 and 5000
+               * 0/100/0 allows any values between 0 and 100
+               * both values can be combined: 0/5000/1000,0/100/0
+         -->
+         <dimension name="ELEVATION" type="intervals" default="0">0/5000/1000</dimension>	 
 
 
-         <!-- todo: example support for ISO8601 date/time and sqlite dimensions -->
+         <!-- coming in a future version: support for ISO8601 date/time dimensions -->
 
       </dimensions>
    </tileset>