Constify engine/eng_cnf.c internal method.

simplify and reindent some related code.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1300)

crypto/engine/eng_cnf.c

@@ -14,11 +14,11 @@
 
 /* ENGINE config module */
 
-static char *skip_dot(char *name)
+static const char *skip_dot(const char *name)
 {
-    char *p;
-    p = strchr(name, '.');
-    if (p)
+    const char *p = strchr(name, '.');
+
+    if (p != NULL)
         return p + 1;
     return name;
 }
@@ -38,14 +38,14 @@ static int int_engine_init(ENGINE *e)
     return 1;
 }
 
-static int int_engine_configure(char *name, char *value, const CONF *cnf)
+static int int_engine_configure(const char *name, const char *value, const CONF *cnf)
 {
     int i;
     int ret = 0;
     long do_init = -1;
     STACK_OF(CONF_VALUE) *ecmds;
     CONF_VALUE *ecmd = NULL;
-    char *ctrlname, *ctrlvalue;
+    const char *ctrlname, *ctrlvalue;
     ENGINE *e = NULL;
     int soft = 0;
 

crypto/engine/eng_ctrl.c

@@ -241,15 +241,15 @@ int ENGINE_ctrl_cmd_string(ENGINE *e, const char *cmd_name, const char *arg,
     int num, flags;
     long l;
     char *ptr;
+
     if ((e == NULL) || (cmd_name == NULL)) {
         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
                   ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
-    if ((e->ctrl == NULL) || ((num = ENGINE_ctrl(e,
-                                                 ENGINE_CTRL_GET_CMD_FROM_NAME,
-                                                 0, (void *)cmd_name,
-                                                 NULL)) <= 0)) {
+    if (e->ctrl == NULL 
+        || (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
+                              0, (void *)cmd_name, NULL)) <= 0) {
         /*
          * If the command didn't *have* to be supported, we fake success.
          * This allows certain settings to be specified for multiple ENGINEs
@@ -270,8 +270,9 @@ int ENGINE_ctrl_cmd_string(ENGINE *e, const char *cmd_name, const char *arg,
                   ENGINE_R_CMD_NOT_EXECUTABLE);
         return 0;
     }
-    if ((flags =
-         ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num, NULL, NULL)) < 0) {
+
+    flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num, NULL, NULL);
+    if (flags < 0) {
         /*
          * Shouldn't happen, given that ENGINE_cmd_is_executable() returned
          * success.