Fixed Travis CI issue where jobs were/are getting stalled while fetching packages.

Something on Travis CI's side has changed such that invoking the 'wait' command within a script attempts to wait on some other jobs in addition to those spawned within the CI job.

Workaround is to explicitly collect the PIDs for processes spawned within the script and only wait on those.

tools/test/travis-ci/functions.sh

@@ -93,6 +93,9 @@ _fetch_deps()
 {
   local pkg="${1}"
   local dep_list="${2}"
+  local pid_list=""
+
+  local PID;
 
   info "Fetching '${pkg}' archives"
 
@@ -103,9 +106,17 @@ _fetch_deps()
       || die "Download failed ('${dep}')" \
       && info "Fetched ${deps_url}/${dep}.deb" &
 
+    PID=$!
+    pid_list="${pid_list} ${PID}"
+
   done <<< "${dep_list}"
 
-  wait
+  # Ignoring shellcheck warning, since we need to allow parameter expansion to
+  #  turn the list string into parametesr.
+  # shellcheck disable=SC2086
+  wait ${pid_list}
+
+  info "Fetch completed."
 }