Fixed a bug that fails to parse hostname starting with numbers.
According to RFC 1123, hostnames that begin with numbers are valid.

(cherry picked from commit 07ff51f43f48d896d6b580279b527f793f387946)
Merge pull request #96 from rhc54/cmr/hostfile

Fixed a bug that fails to parse hostname starting with numbers.
Merge remote-tracking branch 'release/v1.8' into topic/sync
Revert "adding https://github.com/open-mpi/ompi-release/pull/82 PR"

This reverts commit 7673de165c6ef27807b4262781a67ef2530eafa4.
Pull over Jeff's original patch. Update it per George's comments: since opal_using_threads is always false if thread-multiple hasn't been enabled, there is no reason to include checks for it in that condition. So restore the #if statements in opal/threads/mutex.h to regain the remaining missing performance. Also, restore the thread debugging code as there is no reason to exclude it as it only builds in debug environments
Merge pull request #19 from miked-mellanox/topic/sync

sync with ompi-release/v1.8