build: Execute ldconfig to build cache.

build: Execute ldconfig to build cache.

On some platforms a multiarch approach is used for libraries.
The build system does not take this into account and still
places libraries into the lib directory if no --libdir is
specified to configure. On initial startup this results in
libasteriskssl.so not being found, as it is not in the multiarch
lib directory.

This change does the minimally invasive thing and executes
ldconfig so that the libraries in the lib directory are found
and their location cached. By doing so Asterisk starts up fine.

If DESTDIR is specified, however, the old logic is executed as
the install process may not have permission to alter the ldconfig
cache.

ASTERISK-26705

Change-Id: If4eca46ac510c6fea5568256280ffdb3888d7bb4