BUG/MINOR: log: fix a typo that would cause %HP to log <BADREQ>

Typo was introduced in 57bc891 ("BUG/MEDIUM: log: fix risk of
segfault when logging HTTP fields in TCP mode") which inverted the
condition in the test and caused <BADREQ> to be logged when using
%HP.

Signed-off-by: Nenad Merdanovic <nmerdan@anine.io>
diff --git a/src/log.c b/src/log.c
index dffef54..2d02247 100644
--- a/src/log.c
+++ b/src/log.c
@@ -1917,7 +1917,7 @@
 				while (spc < end && *spc != '?' && !HTTP_IS_SPHT(*spc))
 					spc++;
 
-				if (!txn || txn->uri || nspaces == 0) {
+				if (!txn || !txn->uri || nspaces == 0) {
 					chunk.str = "<BADREQ>";
 					chunk.len = strlen("<BADREQ>");
 				} else {