screen_ui: Drop the dependency on common.h.

Remove the use of fopen_path() in screen_ui.cpp, as this is the only
place that requires the dependency on common.h. The mounting work should
be done by the caller.

Also change the parameter in RecoveryUI::ShowFile() from const char* to
const std::string&.

Test: mmma -j bootable/recovery
Test: Build and boot into recovery image on angler. Choose 'View
      recovery logs'.
Change-Id: I8e63f14a8e2b12b856e5a92476e4226cd6ea39fb
diff --git a/recovery.cpp b/recovery.cpp
index 7e539ce..dc2cc08 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -820,7 +820,7 @@
         std::bind(&Device::HandleMenuKey, device, std::placeholders::_1, std::placeholders::_2));
     if (entries[chosen_item] == "Back") break;
 
-    ui->ShowFile(entries[chosen_item].c_str());
+    ui->ShowFile(entries[chosen_item]);
   }
 }