Plug a memory leak

Addressing this OpenScanHub issue:
1. Defect type: RESOURCE_LEAK
5. openscap-1.4.1/src/XCCDF_POLICY/xccdf_policy_remediate.c:726:3: alloc_arg: "oscap_pcre_compile" allocates memory that is stored into "err".
19. openscap-1.4.1/src/XCCDF_POLICY/xccdf_policy_remediate.c:774:2: leaked_storage: Variable "err" going out of scope leaks the storage it points to.
   772|   		oscap_pcre_free(tab[i].re);
   773|
   774|-> 	return ret;
   775|   }
   776|

src/XCCDF_POLICY/xccdf_policy_remediate.c

@@ -707,7 +707,7 @@ struct blueprint_customizations {
 
 static inline int _parse_blueprint_fix(const char *fix_text, struct blueprint_customizations *customizations)
 {
-	char *err;
+	char *err = NULL;
 	int errofs;
 	int ret = 0;
 
@@ -768,6 +768,7 @@ static inline int _parse_blueprint_fix(const char *fix_text, struct blueprint_cu
 	}
 
 exit:
+	oscap_pcre_err_free(err);
 	for (int i = 0; tab[i].pattern != NULL; i++)
 		oscap_pcre_free(tab[i].re);