mdmon: prevent allocations due to late binding

mdmon: prevent allocations due to late binding

Current versions of glibc do not provide a useable interface to clone(2) as it
inflicts hidden dependencies on setting up a glibc specific tls
descriptor.  The dynamic linker trips this dependency and causes mdmon
to intermittently fail to load.  Resolving all dynamic linking prior to
starting the monitor thread appears to mitigate the issue but there is no
guarantee that another tls dependency will bite us later.

However, while the debate continues with the glibc maintainers it seems
prudent to keep this change.  It ensures that we do not get into a
situation where the monitor thread needs to make a late allocation to
resolve a symbol.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>