Make the license format name:count delimiter consistent.

Asterisk '*' was being used in 2.4, and replaced with colon ':' in 2.5.
But liense_list_to_string was missed, and was still using an asterisk
until now. Since we've internally used both up until 18.08, license parsing
code will need to respect both delimiters until two versions past 18.08.

Bug 5630.