This patch does the following :
1) Errors out if similar type of filters args are passed
Eg :
cinder list --name abc --name xyz
cinder list --name abc --filters name=xyz
2) Allows multiple filter parameters of different type
cinder list --filters name=abc --filters size=1
Change-Id: I2f8662555f830b0821147324849d04e7a29d0580