Avoid useless './' in file paths

Replaced useless 'os.path.relpath(os.getcwd())' statement with 'os.curdir' (which is equal to '.').

Signed-off-by: JoeLametta <JoeLametta@users.noreply.github.com>

whipper/common/program.py

@@ -239,6 +239,8 @@ class Program:
         # Avoid filtering non str type values, replace None with empty string
         v_fltr = {k: self._filter.filter(v2) if isinstance(v2, str) else ''
                   if v2 is None else v2 for k, v2 in v.items()}
+        if outdir == os.curdir:
+            return template % v_fltr  # Avoid useless './' in file paths
         return os.path.join(outdir, template % v_fltr)
 
     @staticmethod