RPM_BUILD_ROOT path not correct when use rpmbuild -bb

[shijinkui]

current build rpm use: rpmbuild -bb in RpmHelper, there no need to write RPM_BUILD_ROOT as source build path, should be unpackaged path, or as a user defined source path if use "rpmbuild -bs"

private[this] def installSection(root: File): String = {
    val sb = new StringBuilder
    sb append "\n"
    sb append "%install\n"
    sb append "if [ -e \"$RPM_BUILD_ROOT\" ]; "
    sb append "then\n"
    sb append "  mv \""
    sb append root.getAbsolutePath
    sb append "\"/* \"$RPM_BUILD_ROOT\"\n"
    sb append "else\n"
    sb append "  mv \""
    sb append root.getAbsolutePath
    sb append "\" \"$RPM_BUILD_ROOT\"\n"
    sb append "fi\n"
    sb.toString
  }