Fix cstyle.pl warnings

As of perl v5.22.1 the following warnings are generated:

• Redundant argument in printf at scripts/cstyle.pl line 194

• Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/\S{ <-- HERE / at scripts/cstyle.pl line 608.

They have been addressed by escaping the left braces and by
providing the correct number of arguments to printf based on
the fmt specifier set by the verbose option.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4723