Fix the static analysis test

Adjust its query so that it doesn't cause a particular false positive.

test-static

@@ -1,8 +1,16 @@
 #!/bin/sh
 # We don't use printf's percent notation with our custom logging mechanism,
-# so the compiler cannot check it for us like it usually does
+# so the compiler cannot check it for us like it usually does.
+#
+# In clang-query terms, the string we're interested in can be found through:
+#   set traversal IgnoreUnlessSpelledInSource
+#   set output dump
+#   match callExpr(callee(functionDecl(
+#     hasName("log_full"))),
+#     hasArgument(5, stringLiteral().bind("format")))
+# However, the tool is too restricted to be useful in a shell script.
 perl -n0777 - "$(dirname "$0")"/xC.c <<-'END'
-	while (/\blog_[^ ]+\s*\([^"()]*"[^"]*%[^%][^"]*"/gm) {
+	while (/\blog_[^ ]+\s*\([^"()]*"[^"]*%\w[^"]*"/gm) {
 		my ($p, $m) = ($`, $&);
 		printf "$ARGV:%d: suspicious log format string: %s...\n",
 			(1 + $p =~ tr/\n//), ($m =~ s/\s+/ /rg);