cmd/install: output missing formula name.

Otherwise if there's no search results then there's no indication what
was being searched for:

```
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
==> Searching for a previously deleted formula (in the last month)...
Error: No previously deleted formula found.
==> Searching taps on GitHub...
Error: No formulae found in taps.
```

Library/Homebrew/cmd/install.rb

@@ -253,6 +253,7 @@ def install
       return
     end
 
+    opoo e
     ohai "Searching for similarly named formulae..."
     formulae_search_results = search_formulae(e.name)
     case formulae_search_results.length