[task/git-tools] Change the GNU --lines argument to the POSIX -l

Changed to awk which handles the formatting differences between the
two versions of wc -- BSD version prefixes the output with spaces,
the GNU version does not.

PHPBB3-9808

git-tools/hooks/commit-msg

@@ -65,7 +65,7 @@ then
 	quit $ERR_LENGTH;
 fi
 
-lines=$(wc --lines "$1" | cut -f1 -d" ");
+lines=$(wc -l "$1" | awk '{ print $1; }');
 expecting=header;
 in_description=0;
 in_empty=0;