MTP: Make MtpDatabase class abstract so we can have multiple implementations

Rename existing test database to MtpSqliteDatabase
This is the first step in transitioning to using the media provider database

Change-Id: I5f36c854c6e76a79137c267b000a52ced803776c
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/media/mtp/MtpServer.h b/media/mtp/MtpServer.h
index 40329c5..42261a9 100644
--- a/media/mtp/MtpServer.h
+++ b/media/mtp/MtpServer.h
@@ -27,7 +27,7 @@
 namespace android {
 
 class MtpStorage;
-class MtpDatabase;
+class MtpSqliteDatabase;
 class MtpProperty;
 
 class MtpServer {
@@ -39,7 +39,7 @@
     // path to our sqlite3 database
     const char*         mDatabasePath;
 
-    MtpDatabase*        mDatabase;
+    MtpSqliteDatabase*  mDatabase;
 
     // current session ID
     MtpSessionID        mSessionID;