[C++] Remove redundant code for issue aeron-io#668.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/cpp/CppGenerator.java

@@ -1473,8 +1473,7 @@ private CharSequence generateArrayProperty(
  indent + " throw std::runtime_error(\"string too large for put%2$s [E106]\");\n" +
  indent + " }\n\n" +
 
- indent + " size_t length = srcLength < %4$d ? srcLength : %4$d;\n" +
- indent + " std::memcpy(m_buffer + m_offset + %3$d, str.data(), length);\n" +
+ indent + " std::memcpy(m_buffer + m_offset + %3$d, str.data(), srcLength);\n" +
  indent + " for (size_t start = srcLength; start < %4$d; ++start)\n" +
  indent + " {\n" +
  indent + " m_buffer[m_offset + %3$d + start] = 0;\n" +
@@ -1491,8 +1490,7 @@ private CharSequence generateArrayProperty(
  indent + " throw std::runtime_error(\"string too large for put%2$s [E106]\");\n" +
  indent + " }\n\n" +
 
- indent + " size_t length = srcLength < %4$d ? srcLength : %4$d;\n" +
- indent + " std::memcpy(m_buffer + m_offset + %3$d, str.c_str(), length);\n" +
+ indent + " std::memcpy(m_buffer + m_offset + %3$d, str.c_str(), srcLength);\n" +
  indent + " for (size_t start = srcLength; start < %4$d; ++start)\n" +
  indent + " {\n" +
  indent + " m_buffer[m_offset + %3$d + start] = 0;\n" +