Issue #12326: don't test the major version of sys.platform

Use startswith, instead of ==, when testing sys.platform to support
new platforms like Linux 3 or OpenBSD 5.

tests/test_bdist_rpm.py

@@ -47,7 +47,7 @@ class BuildRpmTestCase(support.TempdirManager,
 
         # XXX I am unable yet to make this test work without
         # spurious sdtout/stderr output under Mac OS X
-        if sys.platform != 'linux2':
+        if not sys.platform.startswith('linux'):
             return
 
         # this test will run only if the rpm commands are found
@@ -87,7 +87,7 @@ class BuildRpmTestCase(support.TempdirManager,
 
         # XXX I am unable yet to make this test work without
         # spurious sdtout/stderr output under Mac OS X
-        if sys.platform != 'linux2':
+        if not sys.platform.startswith('linux'):
             return
 
         # http://bugs.python.org/issue1533164