Revert "What env vars are sets in travis?"

This reverts commit 975f7104a2bd428acbc7fd6dae54d63c69fff928.
Update checkChplInstall to print error log when env var is set.

When CHPL_CHECK_INSTALL_PRINT_ERROR="true" is set and one or more tests fail,
checkChplInstall will now print the entire start_test log to stdout.
For travis builds, print start_test log when there are failures.

When travis builds fail, print the start_test log so users can see the actual
failures. Otherwise, they need to reproduce on another machine, which may or
may not be possible (especially if it is a platform specific issue).