BUG/MINOR: ssl/cli: 'show ssl cert' escape the first '*' of a filename

BUG/MINOR: ssl/cli: 'show ssl cert' escape the first '*' of a filename

When doing a 'show ssl cert <filename>', prefixing a filename with a '*'
allows to show the uncommited transaction asociated to this filename.

However for people using '*' as the first character of their filename,
there is no way to access this filename.

This patch fixes the problem by allowing to escape the first character
with \.

This should be backported in every stable branches.