Revert "introduce deprecation warnings for legacy parametersets"

As discussed in #2573, this change introduced a serious regression.

Fix #2573

This reverts commit 0d0b01b.

Author: nicoddemus

_pytest/deprecated.py

@@ -30,10 +30,4 @@ class RemovedInPytest4Warning(DeprecationWarning):
 
 MARK_INFO_ATTRIBUTE = RemovedInPytest4Warning(
     "MarkInfo objects are deprecated as they contain the merged marks"
-)
-
-MARK_PARAMETERSET_UNPACKING = RemovedInPytest4Warning(
-    "Applying marks directly to parameters is deprecated,"
-    " please use pytest.param(..., marks=...) instead.\n"
-    "For more details, see: https://docs.pytest.org/en/latest/parametrize.html"
 )

_pytest/mark.py

@@ -6,7 +6,7 @@
 from collections import namedtuple
 from operator import attrgetter
 from .compat import imap
-from .deprecated import MARK_INFO_ATTRIBUTE, MARK_PARAMETERSET_UNPACKING
+from .deprecated import MARK_INFO_ATTRIBUTE
 
 def alias(name, warning=None):
     getter = attrgetter(name)
@@ -61,9 +61,6 @@ def extract_from(cls, parameterset, legacy_force_tuple=False):
         if legacy_force_tuple:
             argval = argval,
 
-        if newmarks:
-            warnings.warn(MARK_PARAMETERSET_UNPACKING)
-
         return cls(argval, marks=newmarks, id=None)
 
     @property