Fix URL sanitisation regexp being too greedy

Error messages containing URLs without passwords could get incorrectly sanitised.

The following command in the error output:
```
git clone 'ssh://chris@localhost:1234/home/chris/src/composer/.git' '/home/chris/src/composer/testing/vendor/composer/composer' && cd '/home/chris/src/composer/testing/vendor/composer/composer' && git remote add composer 'ssh://chris@localhost:1234/home/chris/src/composer/.git' && git fetch composer
```
Got converted to:
```
git clone 'ssh://chris@localhost:***@localhost:1234/home/chris/src/composer/.git' && git fetch composer
```