zoneminder: fix incorrect use of logging.exception. (#7675)

Prior to this change the zoneminder component was attempting to
use logging.exception outside of exception handling code. This
would lead to the traceback module throwing an exception when
trying to work out the traceback for the exception.

This fixes the issue by changing the exception call into a
plain error logging call.

homeassistant/components/zoneminder.py

@@ -109,7 +109,7 @@ def _zm_request(method, api_url, data=None):
             break
 
     else:
-        _LOGGER.exception("Unable to get API response from ZoneMinder")
+        _LOGGER.error("Unable to get API response from ZoneMinder")
 
     try:
         return req.json()