Fixes concerning service sheet reading
Fixes concerning service sheet reading

- indicate which request has incorrect tsp type or mode
- correct wrong reading from excel : if string values contain only a number
  xlrd interprets as a float eg 1 -> 1.0  . A function is used to correct this
  when filling the Request class

Signed-off-by: EstherLerouzic <9136e9bbec0a09a1685b8ebbe677b6c9b26e8f18@orange.com>

Telecominfraproject/gnpy