Patch ESMP to allow loading of config from relative path

Allow ESMP to load configuration relative to the ESMP Python module
so they can be loading when installing. This is requred to allow
a "drag and drop" style install.
Use PYTHON_SITE_PACKAGES rather than GLOBing for module

Rather than GLOBing for ESMP_LoadESMF.py use the variable we
already have.
Merge branch 'esmp-config-fix'