use return instead of exit in functions

bin/epm-remove

@@ -295,7 +295,7 @@ epm_remove()
 
 	if [ -z "$pkg_names" ] ; then
 		warning "no package(s) to remove."
-		exit 0
+		return
 	fi
 	# remove according current arch (if x86_64) by default
 	pkg_names="$(echo $pkg_names | exp_with_arch_suffix)"

bin/epm-upgrade

@@ -46,7 +46,7 @@ epm_upgrade()
 			[ -n "$verbose" ] && info "Packages to upgrade: $installlist"
 			if [ -z "$installlist" ] ; then
 				warning "There is no installed packages for upgrade from task $*"
-				exit 22
+				return 22
 			fi
 
 			try_change_alt_repo