Improve a variable's name

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index ebd19c3..c9cca70 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7947,7 +7947,7 @@
     int ret = 0;
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
         ssl->handshake->ciphersuite_info;
-    int have_ca_chain = 0;
+    int have_ca_chain_or_callback = 0;
 
     if (authmode == MBEDTLS_SSL_VERIFY_NONE) {
         return 0;
@@ -7971,7 +7971,7 @@
 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
     if (ssl->conf->f_ca_cb != NULL) {
         ((void) rs_ctx);
-        have_ca_chain = 1;
+        have_ca_chain_or_callback = 1;
 
         MBEDTLS_SSL_DEBUG_MSG(3, ("use CA callback for X.509 CRT verification"));
         ret = mbedtls_x509_crt_verify_with_ca_cb(
@@ -7999,7 +7999,7 @@
         }
 
         if (ca_chain != NULL) {
-            have_ca_chain = 1;
+            have_ca_chain_or_callback = 1;
         }
 
         ret = mbedtls_x509_crt_verify_restartable(
@@ -8061,7 +8061,7 @@
         ret = 0;
     }
 
-    if (have_ca_chain == 0 && authmode == MBEDTLS_SSL_VERIFY_REQUIRED) {
+    if (have_ca_chain_or_callback == 0 && authmode == MBEDTLS_SSL_VERIFY_REQUIRED) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("got no CA chain"));
         ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
     }