[FAB-9974] Configtxgen recover profile not found panic
[FAB-9974] Configtxgen recover profile not found panic

This CR updates configtxgen's error handling logic to recover from
"Could not find profile", which is now the most likely error for a
user/developer to hit (since viper is now initialized with the
sampleconfig dir when the FABRIC_CFG_PATH is not set, it will always
find a configtx.yaml but that yaml won't necessarily contain the
requested profile).

Change-Id: I8e191c00bdf903253d30f7ef015049f351094ff3
Signed-off-by: Will Lahti <f19a2779710675aad3df5c81e4ecfde11707e3aa@us.ibm.com>

manish-sethi/fabric-sidedb,jimthematrix/fabric,stemlending/fabric,stemlending/fabric,manish-sethi/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,stemlending/fabric,jimthematrix/fabric,muralisrini/fabric,binhn/fabric,manish-sethi/fabric,binhn/fabric,stemlending/fabric,xixuejia/fabric,hyperledger/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric-sidedb,binhn/fabric,xixuejia/fabric,muralisrini/fabric,hyperledger/fabric,manish-sethi/fabric-sidedb,xixuejia/fabric,manish-sethi/fabric-sidedb