Remove useless cat, and replace backtick

cat is a tool for con"cat"enating files. Reading a single file
as input to a program is considered a Useless Use Of Cat (UUOC).
It's more efficient and less roundabout to simply give file as input.

Also use $(..) instead of legacy `..`
Backtick command substitution `..` is legacy syntax with several issues.
It has a series of undefined behaviors related to quoting in POSIX.
It imposes a custom escaping mode with surprising results.
It's exceptionally hard to nest.
$(..) command substitution has none of these problems, and is therefore strongly encouraged.

Change-Id: Ia668c6323660641bbb5084ee824ae9ae7631c76f
Reviewed-on: https://gerrit.libreoffice.org/32473Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>

solenv/bin/bin_library_info.sh

@@ -34,7 +34,7 @@ die()
 get_config_sha()
 {
     pushd ${SRCDIR?} > /dev/null
-    cat ${BUILDDIR?}/config_host.mk | git hash-object --stdin
+    git hash-object ${BUILDDIR?}/config_host.mk
     popd > /dev/null
 }
 

sysui/desktop/share/apparmor.sh

@@ -37,10 +37,10 @@ INST_ROOT_FORMAT=${INST_ROOT_FORMAT////.}
 #Need to escape / for sed
 INST_ROOT_SED=${INST_ROOT////\\/}
 
-for filename in `ls $PROFILESFROM`
+for filename in $(ls $PROFILESFROM)
 do
     tourl=$INSTALLTO$INST_ROOT_FORMAT$filename
-    cat $PROFILESFROM$filename | sed "s/INSTDIR-/$INST_ROOT_SED/g" > $tourl
+    sed "s/INSTDIR-/$INST_ROOT_SED/g" $PROFILESFROM$filename > $tourl
     echo "$tourl"
 
 done