ssh.softwareversion: allow more characters

The keyword would not allow matching on "OpenSSH_5.5p1 Debian-6+squeeze5"
as the + and space characters were not allowed.

This patch adds support for them.

src/detect-ssh-software-version.c

@@ -61,7 +61,7 @@
 /**
  * \brief Regex for parsing the softwareversion string
  */
-#define PARSE_REGEX  "^\\s*\"?\\s*?([0-9a-zA-Z\\.\\-\\_]+)\\s*\"?\\s*$"
+#define PARSE_REGEX  "^\\s*\"?\\s*?([0-9a-zA-Z\\.\\-\\_\\+\\s+]+)\\s*\"?\\s*$"
 
 static pcre *parse_regex;
 static pcre_extra *parse_regex_study;