CPackRPM: avoid leakage of RPM directive from one component to another.

Fixes #0013248
Inspired-By: Sergei Golubchik

Modules/CPackRPM.cmake

@@ -488,7 +488,10 @@ FOREACH(_RPM_SPEC_HEADER URL REQUIRES SUGGESTS PROVIDES OBSOLETES PREFIX CONFLIC
       MESSAGE("CPackRPM:Debug: User defined ${_PACKAGE_HEADER_NAME}:\n ${CPACK_RPM_PACKAGE_${_RPM_SPEC_HEADER}_TMP}")
     ENDIF(CPACK_RPM_PACKAGE_DEBUG)
     SET(TMP_RPM_${_RPM_SPEC_HEADER} "${_PACKAGE_HEADER_NAME}: ${CPACK_RPM_PACKAGE_${_RPM_SPEC_HEADER}_TMP}")
-ENDIF(CPACK_RPM_PACKAGE_${_RPM_SPEC_HEADER}_TMP)
+  ELSE(CPACK_RPM_PACKAGE_${_RPM_SPEC_HEADER}_TMP)
+    # Do not forget to unset previously set header (from previous component)
+    UNSET(TMP_RPM_${_RPM_SPEC_HEADER})
+  ENDIF(CPACK_RPM_PACKAGE_${_RPM_SPEC_HEADER}_TMP)
 ENDFOREACH(_RPM_SPEC_HEADER)
 
 # CPACK_RPM_SPEC_INSTALL_POST