Support 2.x apps which use their own shared libraries

Support 2.x apps which use their own shared libraries

Some applications from Tizen 2.x were compiled with '-rpath'
pointing at their lib directory which starts as '/opt/usr/apps/...'.
But this path is not adapted to Tizen 3.0.

We cannot set LD_LIBRARY_PATH directly by some security issues,
we make the loader have empty rpath to the dynamic linker looks in the CWD
forcely. And then, change working directory before calling dlopen() to
find libraries well.

Change-Id: I8111e5ca087ea07c52866d77deb7f53332957346
Signed-off-by: Sangyoon Jang <s89.jang@samsung.com>