configtxgen is unable to read in the sample V1.1 profiles due to the
period in the profile name as defined in sampleconfig/configtx.yaml
(e.g. SampleSingleMSPChannelV1.1). This CR updates the profile names
to use underscores instead so Viper is able to locate and load them
as expected.

Change-Id: Ic7bf03199c20eca466519c406c702221b071602c
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>