SF bug #417093: Case sensitive import: dir and .py file w/ same name

Directory containing
    Spam.py
    spam/__init__.py
Then "import Spam" caused a SystemError, because code checking for
the existence of "Spam/__init__.py" finds it on a case-insensitive
filesystem, but then bails because the directory it finds it in
doesn't match case, and then old code assumed that was still an error
even though it isn't anymore.  Changed the code to just continue
looking in this case (instead of calling it an error).  So
    import Spam
and
    import spam
both work now.

Python/import.c

@@ -958,14 +958,11 @@ find_module(char *realname, PyObject *path, char *buf, size_t buflen,
 		/* Check for package import (buf holds a directory name,
 		   and there's an __init__ module in that directory */
 #ifdef HAVE_STAT
-		if (stat(buf, &statbuf) == 0 &&
-		    S_ISDIR(statbuf.st_mode) &&
-		    find_init_module(buf)) {
-			if (case_ok(buf, len, namelen, name))
+		if (stat(buf, &statbuf) == 0 &&       /* it exists */
+		    S_ISDIR(statbuf.st_mode) &&       /* it's a directory */
+		    find_init_module(buf) &&          /* it has __init__.py */
+		    case_ok(buf, len, namelen, name)) /* and case matches */
 			return &fd_package;
-			else
-				return NULL;
-		}
 #else
 		/* XXX How are you going to test for directories? */
 #ifdef RISCOS