Remove useless refCounting from FileMap.

Nobody ever called acquire() so release() was always
equivalent to delete. Just use delete instead so that
people can use unique_ptr directly (or shared_ptr if
they really want refcounts).

Change-Id: I9e3ad5e0f6a4fcc4e02e5a2ff7ef9514fe234415
diff --git a/libutils/FileMap.cpp b/libutils/FileMap.cpp
index 0af066f..91e45d8 100644
--- a/libutils/FileMap.cpp
+++ b/libutils/FileMap.cpp
@@ -48,7 +48,7 @@
 
 // Constructor.  Create an empty object.
 FileMap::FileMap(void)
-    : mRefCount(1), mFileName(NULL), mBasePtr(NULL), mBaseLength(0),
+    : mFileName(NULL), mBasePtr(NULL), mBaseLength(0),
       mDataPtr(NULL), mDataLength(0)
 {
 }
@@ -56,11 +56,6 @@
 // Destructor.
 FileMap::~FileMap(void)
 {
-    assert(mRefCount == 0);
-
-    //printf("+++ removing FileMap %p %zu\n", mDataPtr, mDataLength);
-
-    mRefCount = -100;       // help catch double-free
     if (mFileName != NULL) {
         free(mFileName);
     }
@@ -134,7 +129,6 @@
 
     void* ptr;
 
-    assert(mRefCount == 1);
     assert(fd >= 0);
     assert(offset >= 0);
     assert(length > 0);