Core should stop reporting that an element library wasn't found when dlopen fails

[calewis]

Issue

libmyelement.so is sitting in the correct folder for core to find it. I run sst my_input.py and the error message I get is

FATAL:  SST Core: can't find requested component 'myelement.mycomponent'
Error: unable to find "myelement" element library

How to reproduce

1. Compile element with a missing symbol
2. Try to run sst and use that element

IFF you set SST_CORE_DL_VERBOSE=1 you will get some helpful info, but we really need to stop reporting "unable to find" when dlopen fails. It implies that the .so file wasn't found instead of indicating that something was wrong with the .so file.

[jpkenny]

This has misled me in the past as well. Core should report something less specific than "unable to find", since the library was indeed found.