Revert "Raise exception when a stylesheet is unparsable."

This reverts commit 0400945ac4.

See #2571

CHANGELOG.asciidoc

@@ -61,6 +61,7 @@ Fixed
 - Crash when the key config isn't writable
 - Crash when unbinding an unbound key in the key config
 - Crash when using `:debug-log-filter` when `--filter` wasn't given on startup.
+- Crash with some invalid setting values
 - Various rare crashes
 
 v0.10.1

qutebrowser/utils/log.py

@@ -161,11 +161,6 @@ def stub(suffix=''):
     misc.warning(text)
 
 
-class CriticalQtWarning(Exception):
-
-    """Exception raised when there's a critical Qt warning."""
-
-
 def init_log(args):
     """Init loggers based on the argparse namespace passed."""
     level = args.loglevel.upper()
@@ -424,17 +419,7 @@ def qt_message_handler(msg_type, context, msg):
                 'with: -9805',  # flake8: disable=E131
         ]
 
-    # Messages which will trigger an exception immediately
-    critical_msgs = [
-        'Could not parse stylesheet of object',
-    ]
-
-    if any(msg.strip().startswith(pattern) for pattern in critical_msgs):
-        # For some reason, the stack gets lost when raising here...
-        logger = logging.getLogger('misc')
-        logger.error("Got critical Qt warning!", stack_info=True)
-        raise CriticalQtWarning(msg)
-    elif any(msg.strip().startswith(pattern) for pattern in suppressed_msgs):
+    if any(msg.strip().startswith(pattern) for pattern in suppressed_msgs):
         level = logging.DEBUG
     else:
         level = qt_to_logging[msg_type]