Log Message:
php-composer: Update to 1.10.15

Upstream Release Notes:

1.10.15
 * Fixed path repo version guessing issue

1.10.14
 * Fixed version guesser to look at remote branches as well as local ones
 * Fixed path repositories version guessing to handle edge cases where version \ 
is different from the VCS-guessed version
 * Fixed COMPOSER env var causing issues when combined with the global command
 * Fixed a few issues dealing with PHP without openssl extension (not \ 
recommended at all but sometimes needed for testing)