Rename CacheLocation to Paths.

We have a general need for overriding more paths (e.g. "/tmp"), mostly
for testing purpose. Rename CacheLocation to Paths, and use that to
manage TEMPORARY_{INSTALL,LOG}_FILE.

Test: mmma -j bootable/recovery
Test: recovery_component_test
Change-Id: Ia8ce8e5695df37ca434f13ac4d3206de1e8e9396
diff --git a/common.h b/common.h
index 8b336f8..a851306 100644
--- a/common.h
+++ b/common.h
@@ -17,8 +17,8 @@
 #ifndef RECOVERY_COMMON_H
 #define RECOVERY_COMMON_H
 
-#include <stdio.h>
 #include <stdarg.h>
+#include <stdio.h>
 
 #include <string>
 
@@ -38,7 +38,7 @@
 extern const char* reason;
 
 // fopen a file, mounting volumes and making parent dirs as necessary.
-FILE* fopen_path(const char *path, const char *mode);
+FILE* fopen_path(const std::string& path, const char* mode);
 
 void ui_print(const char* format, ...);