Update install_namd.sh to remove branch checkout

Removed git checkout command for branch 'fix_imdv3'.

Author: ljwoods2

docker/namd/install_namd.sh

@@ -12,7 +12,6 @@ export NPROC=$(nproc)
 # Setup NAMD
 git clone https://oauth2:$(cat /run/secrets/NAMD_ACCESS_TOKEN)@gitlab.com/tcbgUIUC/namd.git
 cd namd
-git checkout fix_imdv3
 wget https://github.com/charmplusplus/charm/archive/refs/tags/v8.0.0.tar.gz
 tar xf v8.0.0.tar.gz
 cd charm-8.0.0
@@ -32,4 +31,4 @@ cd Linux-x86_64-g++
 make -j ${NPROC}
 
 mkdir /opt/namd-build
-mv /opt/namd/Linux-x86_64-g++/namd3 /opt/namd-build/
+mv /opt/namd/Linux-x86_64-g++/namd3 /opt/namd-build/