Appply some bugbear suggestions (#761)

B015 Pointless comparison.
B009 Do not call `getattr` with a constant attribute value.

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Co-authored-by: Brett Cannon <brett@python.org>

src/packaging/_manylinux.py

@@ -82,7 +82,7 @@ def _glibc_version_string_confstr() -> Optional[str]:
     # https://github.com/python/cpython/blob/fcf1d003bf4f0100c/Lib/platform.py#L175-L183
     try:
         # Should be a string like "glibc 2.17".
-        version_string: str = getattr(os, "confstr")("CS_GNU_LIBC_VERSION")
+        version_string: Optional[str] = os.confstr("CS_GNU_LIBC_VERSION")
         assert version_string is not None
         _, version = version_string.rsplit()
     except (AssertionError, AttributeError, OSError, ValueError):

tests/test_structures.py

@@ -8,11 +8,11 @@
 
 
 def test_infinity_repr():
-    repr(Infinity) == "Infinity"
+    assert repr(Infinity) == "Infinity"
 
 
 def test_negative_infinity_repr():
-    repr(NegativeInfinity) == "-Infinity"
+    assert repr(NegativeInfinity) == "-Infinity"
 
 
 def test_infinity_hash():