Fix SourceForge bug 1904965 - check_apt: SECURITY_RE is not correct

For the default security upgrade detection regular expression, match
"Debian-Security" in package description when it's anywhere after the
first parenthesis (not just the second space-delimited word). For
example:

... (4.0.1-5.4 Debian:6.0.6/stable, Debian-Security:6.0/stable ...

plugins/check_apt.c

@@ -52,7 +52,7 @@ typedef enum { UPGRADE, DIST_UPGRADE, NO_UPGRADE } upgrade_type;
 /* String found at the beginning of the apt output lines we're interested in */
 #define PKGINST_PREFIX "Inst "
 /* the RE that catches security updates */
-#define SECURITY_RE "^[^\\(]*\\([^ ]* (Debian-Security:|Ubuntu:[^/]*/[^-]*-security)"
+#define SECURITY_RE "^[^\\(]*\\(.* (Debian-Security:|Ubuntu:[^/]*/[^-]*-security)"
 
 /* some standard functions */
 int process_arguments(int, char **);