Fix install script syntax error (#1805)

Fix hip-nvcc install warning on postinstall and prerm script

[ROCm/hip commit: f653c8c999]

projects/hip/packaging/hip-nvcc.postinst

@@ -3,6 +3,6 @@
 ROCMDIR=@ROCM_PATH@
 HIPDIR=$ROCMDIR/hip
 
-if [ -d $ROCMDIR]
+if [ -d $ROCMDIR] ; then
     ln -s -f $ROCMDIR /opt/rocm
 fi

projects/hip/packaging/hip-nvcc.prerm

@@ -1,5 +1,5 @@
 #!/bin/bash
 
-if [ -L "/opt/rocm" ]
+if [ -L "/opt/rocm" ] ; then
    unlink /opt/rocm
 fi