Remove the unnecessary conda activate in the BWA recipe

recipes/Singularity.bwa

 Bootstrap: debootstrap
 OSVersion: bionic
 MirrorURL: http://us.archive.ubuntu.com/ubuntu/
-
+Include: software-properties-common
 %post
-    apt update
-    apt install -y software-properties-common
     apt-add-repository universe
-    apt update
-    apt install -y wget
+    apt install -y wget bzip2
     wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda3.sh
-    bash miniconda3.sh -b -p "$HOME"/miniconda
-    export PATH="$HOME/miniconda/bin:$PATH"
-    echo "PATH=$HOME/miniconda/bin:$PATH" >> "$SINGULARITY_ENVIRONMENT"
-    . ./$HOME/miniconda/bin/activate
+    bash miniconda3.sh -b -p /opt/miniconda
+    export PATH="/opt/miniconda/bin:$PATH"
+    echo "PATH=/opt/miniconda/bin:$PATH" >> "$SINGULARITY_ENVIRONMENT"
     conda install -y -c bioconda bwa
 
 %test
-    export PATH="$HOME/miniconda/bin:$PATH"
+    export PATH="/opt/miniconda/bin:$PATH"
     command -v conda >/dev/null 2>&1 || exit 1
     command -v bwa >/dev/null 2>&1 || exit 1