libcacard: remove useless initializers

libcacard has many functions which initializes local variables
at declaration time, which are always assigned some values later
(often right after declaration).  Clean up these initializers.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/libcacard/vcard.c b/libcacard/vcard.c
index 227e477..6aaf085 100644
--- a/libcacard/vcard.c
+++ b/libcacard/vcard.c
@@ -166,8 +166,8 @@
 void
 vcard_free(VCard *vcard)
 {
-    VCardApplet *current_applet = NULL;
-    VCardApplet *next_applet = NULL;
+    VCardApplet *current_applet;
+    VCardApplet *next_applet;
 
     if (vcard == NULL) {
         return;