test/librados/c_read_operations.cc: fix invalid checks

Wrong variable for return of rados_getxattrs_next() and
rados_omap_get_next() used (len vs. val_len).

Fix for:

CID 1219464 (#1 of 1): Logically dead code (DEADCODE)
 dead_error_line: Execution cannot reach this expression
 key == NULL inside statement if (len == 0UL && key == NU...

CID 1219465 (#1 of 1): Logically dead code (DEADCODE)
 dead_error_line: Execution cannot reach this expression
 key == NULL inside statement if (len == 0UL && key == NU...

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>

Author: dalgaaf

src/test/librados/c_read_operations.cc

@@ -70,7 +70,7 @@ class CReadOpsTest : public RadosTest {
     size_t val_len = 0;
     while (i < len) {
       ASSERT_EQ(0, rados_omap_get_next(iter, &key, &val, &val_len));
-      if (len == 0 && key == NULL && val == NULL)
+      if (val_len == 0 && key == NULL && val == NULL)
 	break;
       if (key)
 	EXPECT_EQ(std::string(keys[i]), std::string(key));
@@ -101,7 +101,7 @@ class CReadOpsTest : public RadosTest {
     while (i < len) {
       ASSERT_EQ(0, rados_getxattrs_next(iter, (const char**) &key,
 					(const char**) &val, &val_len));
-      if (len == 0 && key == NULL && val == NULL)
+      if (val_len == 0 && key == NULL && val == NULL)
 	break;
       EXPECT_EQ(std::string(keys[i]), std::string(key));
       EXPECT_EQ(0, memcmp(vals[i], val, val_len));