log_services: Fix isContentTypeAllowed checks

The commit https://gerrit.openbmc.org/c/openbmc/bmcweb/+/56694
inadvertently changed the polarity on the if checks using the newly
introduced isContentTypeAllowed function which caused 'Bad Request' to
be returned when the content type was allowed.

Tested:
Getting the EventLog and PostCodes attachment would return the data
instead of 'Bad Request'.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Iafcdeaba1a0723326347bb2a832b53bbf0aab230
diff --git a/redfish-core/lib/log_services.hpp b/redfish-core/lib/log_services.hpp
index f549397..5159ae1 100644
--- a/redfish-core/lib/log_services.hpp
+++ b/redfish-core/lib/log_services.hpp
@@ -1941,7 +1941,7 @@
         {
             return;
         }
-        if (http_helpers::isContentTypeAllowed(
+        if (!http_helpers::isContentTypeAllowed(
                 req.getHeaderValue("Accept"),
                 http_helpers::ContentType::OctetStream, true))
         {
@@ -4008,7 +4008,7 @@
         {
             return;
         }
-        if (http_helpers::isContentTypeAllowed(
+        if (!http_helpers::isContentTypeAllowed(
                 req.getHeaderValue("Accept"),
                 http_helpers::ContentType::OctetStream, true))
         {