Change the API of bccPrepareRelocatable().

Remove the caching from this function. It makes the API simpler
and intuitive. OBJPATH in the prototype is the path of the output
relocatable object file.

Change-Id: I03c423661a5ad306e8a18e30c838770a00a37f55
diff --git a/lib/ExecutionEngine/bcc.cpp b/lib/ExecutionEngine/bcc.cpp
index 6a20105..057be50 100644
--- a/lib/ExecutionEngine/bcc.cpp
+++ b/lib/ExecutionEngine/bcc.cpp
@@ -126,8 +126,7 @@
 
 
 extern "C" int bccPrepareRelocatable(BCCScriptRef script,
-                                     char const *cacheDir,
-                                     char const *cacheName,
+                                     char const *objPath,
                                      bccRelocModelEnum RelocModel,
                                      unsigned long flags) {
   BCC_FUNC_LOGGER();
@@ -156,7 +155,7 @@
     }
   }
 
-  return unwrap(script)->prepareRelocatable(cacheDir, cacheName, RM, flags);
+  return unwrap(script)->prepareRelocatable(objPath, RM, flags);
 }