sqlite3: Enabling option to disable filesystem locking (POSIX advisory locks)

When sqlite database is expected to be stored on a NFS disk (e.g., a
home directory and ~/.ndnx/ndnsec-public-info.db is on NFS mount),
default POSIX advisory filesystem locks may not work properly, since
some NFS implementation do not support them.  This commit allows
specification of ``--without-sqlite-locking`` to use alternative
"dotfile" sqlite locking mechanism.

Change-Id: Iddee82c6ca7839f993147547f61c440184689043
diff --git a/src/security/sec-public-info-sqlite3.cpp b/src/security/sec-public-info-sqlite3.cpp
index 7e6f4c8..43dc641 100644
--- a/src/security/sec-public-info-sqlite3.cpp
+++ b/src/security/sec-public-info-sqlite3.cpp
@@ -88,9 +88,16 @@
 {
   boost::filesystem::path identityDir = boost::filesystem::path(getenv("HOME")) / ".ndnx";
   boost::filesystem::create_directories (identityDir);
-  
-  int res = sqlite3_open((identityDir / "ndnsec-public-info.db").c_str(), &m_database);
 
+  /// @todo Add define for windows/unix in wscript. The following may completely fail on windows
+  int res = sqlite3_open_v2((identityDir / "ndnsec-public-info.db").c_str(), &m_database,
+                            SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
+#ifdef DISABLE_SQLITE3_FS_LOCKING
+                            "unix-dotfile"
+#else
+                            0
+#endif
+                            );
   if (res != SQLITE_OK)
     throw Error("identity DB cannot be opened/created");