fix syntax error in do_raw_disk_image_shrink_rootfs

Calling "mender-convert raw-disk-image-shrink-rootfs" gave this:

$ ./mender-convert raw-disk-image-shrink-rootfs --raw-disk-image input/2018-11-13-raspbian-stretch-lite-expanded-16gb.img
*** Data partition size set to default value: 128MB ***
*** Total storage size set to default value: 8GB ***
1/1 Shrinking raw disk image root filesystem...
./mender-convert: line 191: local: `=': not a valid identifier
./mender-convert: line 191: local: `512': not a valid identifier
./mender-convert: line 201: 98304 * : syntax error: operand expected (error token is "* ")

Changelog: Fix syntax error when calling "mender-convert raw-disk-image-shrink-rootfs"

Signed-off-by: Mirza Krak <mirza.krak@northern.tech>

mender-convert

@@ -190,7 +190,7 @@ do_raw_disk_image_shrink_rootfs() {
 
   # Gather information about raw disk image.
   get_raw_disk_sizes ${raw_disk_image} raw_disk_counts raw_disk_sizes
-  local sector_size = ${raw_disk_sizes[sector_size]}
+  local sector_size=${raw_disk_sizes[sector_size]}
 
   # Find first available loopback device.
   loopdevice=($(losetup -f))