Removed -e option (#616)

The -e option exits immediately on an error, which will cause the
command to exit if no version manager is detected. This means we won't
try to invoke elixir from the path.

From my limited knowledge of bash, it looks like this command was
added in error.

Fixes #615

bin/start_lexical.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -eo pipefail
+set -o pipefail
 
 script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)"