Try to fix the Travis test failures

It seems expect prioritizes the first pattern in the list, instead of
the pattern that matches earliest in the buffer. That seems pretty
stupid, but let's try moving the prompt pattern to the end and see if
that fixes the Travis failures.

tests/interactive.expect.rc

@@ -143,7 +143,7 @@ proc expect_prompt {args} {
     } else {
         log_info "expecting prompt $prompt_counter"
     }
-    set expargs [concat $prompt_pat [list $prompt_action] $expargs]
+    set expargs [concat $expargs $prompt_pat [list $prompt_action]]
     expect {*}$expargs
     incr prompt_counter
 }