Fix some Coverity warnings

Check some return values on some functions.
Reviewed-by: NTim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7335)

(cherry picked from commit 434893af2bd4c1fa72655f8e5262c8a432713968)

crypto/evp/e_rc2.c

@@ -92,7 +92,8 @@ static int rc2_meth_to_magic(EVP_CIPHER_CTX *e)
 {
     int i;
 
-    EVP_CIPHER_CTX_ctrl(e, EVP_CTRL_GET_RC2_KEY_BITS, 0, &i);
+    if (EVP_CIPHER_CTX_ctrl(e, EVP_CTRL_GET_RC2_KEY_BITS, 0, &i) <= 0)
+        return 0;
     if (i == 128)
         return RC2_128_MAGIC;
     else if (i == 64)
@@ -136,8 +137,9 @@ static int rc2_get_asn1_type_and_iv(EVP_CIPHER_CTX *c, ASN1_TYPE *type)
             return -1;
         if (i > 0 && !EVP_CipherInit_ex(c, NULL, NULL, NULL, iv, -1))
             return -1;
-        EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_RC2_KEY_BITS, key_bits, NULL);
-        if (EVP_CIPHER_CTX_set_key_length(c, key_bits / 8) <= 0)
+        if (EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_RC2_KEY_BITS, key_bits,
+                                NULL) <= 0
+                || EVP_CIPHER_CTX_set_key_length(c, key_bits / 8) <= 0)
             return -1;
     }
     return i;