tests: add hg10 requirement to test-check-module-imports.t

This requirement exists to make sure for hg has locate command, which is used
in this test file for getting a list of files to check. Since in theory current
versions of tests could be run on older hg, it doesn't hurt to mark even this
version requirement (as old as it is).

See also: a29f071751df.

tests/test-check-module-imports.t

@@ -1,4 +1,4 b''
-#require test-repo
+#require test-repo hg10
 
   $ . "$TESTDIR/helpers-testrepo.sh"
   $ import_checker="$TESTDIR"/../contrib/import-checker.py