e2fsprogs: do not use ldconfig when building the host variant

e2fsprogs: do not use ldconfig when building the host variant

Since commit 93acaa5a573865afc7a8c0912a7037965eb845a6 ("e2fsprogs:
build shared library for the host"), we are building shared libraries
in host-e2fsprogs instead of static libraries. A consequence of this
is that the e2fsprogs build system tries to run ldconfig on the host,
which fails when running as non-root:

/usr/sbin/ldconfig: Can't create temporary cache file /etc/ld.so.cache~: Permission denied
make[3]: [Makefile:441: install-shlibs] Error 1 (ignored)

Tell the configure script to use "true" as ldconfig in order to avoid
this problem.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>