By Balazs Koranyi WASHINGTON (Reuters) – European Central Bank policymakers are keen to end their bond purchase scheme at the earliest possible moment and raise interest rates as soon as July but certainly no later than September, nine sources familiar with ECB thinking told Reuters. The ECB has been removing stimulus at the slowest possible pace this year but a surge in inflation is now putting pressure on policymakers to end their nearly decade-long experiment with unconventional support. The big obstacle so far has been that longer-term forecasts still showed inflation falling back below th…