Trac #34717: Check the presence of lrsnash for obtain_nash()

To fix failures like
{{{
File "src/sage/game_theory/catalog_normal_form_games.py", line 916, in
sage.game_theory.catalog_normal_form_games.TravellersDilemma
Failed example:
    g.obtain_nash()
Exception raised:
    Traceback (most recent call last):
      File "/Users/kwankyu/GitHub/sage-dev/src/sage/doctest/forker.py",
line 695, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/Users/kwankyu/GitHub/sage-dev/src/sage/doctest/forker.py",
line 1093, in compile_and_execute
        exec(compiled, globs)
      File "<doctest
sage.game_theory.catalog_normal_form_games.TravellersDilemma[8]>", line
1, in <module>
        g.obtain_nash()
      File "/Users/kwankyu/GitHub/sage-
dev/src/sage/game_theory/normal_form_game.py", line 1688, in obtain_nash
        return self._solve_lrs(maximization)
      File "/Users/kwankyu/GitHub/sage-
dev/src/sage/game_theory/normal_form_game.py", line 1758, in _solve_lrs
        LrsNash().require()
      File "/Users/kwankyu/GitHub/sage-
dev/src/sage/features/__init__.py", line 209, in require
        raise FeatureNotPresentError(self, presence.reason,
presence.resolution)
    sage.features.FeatureNotPresentError: lrsnash is not available.
    Executable 'lrsnash' not found on PATH.
    No equivalent system packages for homebrew are known to Sage.
    To install lrsnash using the Sage package manager, you can try to
run:
      !sage -i lrslib
    No equivalent system packages for pip are known to Sage.
    Further installation instructions might be available at
http://cgm.cs.mcgill.ca/~avis/C/lrs.html.
}}}
I have been seeing these failures for a long time on my system (mac os).

URL: https://trac.sagemath.org/34717
Reported by: klee
Ticket author(s): Matthias Koeppe
Reviewer(s): Kwankyu Lee

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=9816c00fcfc3ba11d0a9b61033df4915a15ccf0b
-md5=dff4e185544cf5dd1f2bbeb4f4761cbf
-cksum=655542759
+sha1=c39297a2d58601cfa6baa9045140c3485ee9ffab
+md5=534693f57e442ff0cd9e4cfbc4768ebc
+cksum=82888323

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-0e1a60596d521bf69572e1484066f4015749735e
+2c3a4cef8d3ce703174c93a92ed0efcbecdd36ba

src/sage/game_theory/normal_form_game.py

@@ -1674,17 +1674,17 @@ def obtain_nash(self, algorithm=False, maximization=True, solver=None):
         if not self._is_complete():
             raise ValueError("utilities have not been populated")
 
-        from sage.features.lrs import Lrs
+        from sage.features.lrs import LrsNash
         if not algorithm:
             if self.is_constant_sum():
                 algorithm = "lp"
-            elif Lrs().is_present():
+            elif LrsNash().is_present():
                 algorithm = "lrs"
             else:
                 algorithm = "enumeration"
 
         if algorithm == "lrs":
-            Lrs().require()
+            LrsNash().require()
             return self._solve_lrs(maximization)
 
         if algorithm == "LCP":