Add Warning when Conda is installed because we skip the virtualenv creation

Fix the case where we could have conda not installed but not setting VirtualEnv still (and have this non relevant warning

scripts/common_startup.sh

@@ -9,6 +9,7 @@ done
 # Conda Python is in use, do not use virtualenv
 if python -V 2>&1 | grep -q -e 'Anaconda' -e 'Continuum Analytics' ; then
     SET_VENV=0
+    CONDA_ALREADY_INSTALLED=1
 fi
 
 DEV_WHEELS=0
@@ -127,6 +128,8 @@ if [ $SET_VENV -eq 1 ]; then
         echo "ERROR: A virtualenv cannot be found. Please create a virtualenv in $GALAXY_VIRTUAL_ENV, or activate one."
         exit 1
     fi
+elif [ $SET_VENV -eq -0 -a $CONDA_ALREADY_INSTALLED -eq 1 ]; then
+    echo -e "\e[33mWarning: You have Conda installed. Skipping virtualenv creation. This could cause missing dependencies.\e[0m"
 fi
 
 : ${GALAXY_WHEELS_INDEX_URL:="https://wheels.galaxyproject.org/simple"}