utils/genrandconfig: increase default target rootfs size to 5G

Since there isn't a way to reliably compute the required size lets
just set it to what should be a high enough value to not run out
of space.

Both ext2 and fsfs create sparse files, so this is not a waste of disk
space.

Fixes:
 - http://autobuild.buildroot.net/results/a3c68cdc515353c0d2650ee743aa3bd8ab99a418
 - http://autobuild.buildroot.net/results/ad426ff903d78a92de8f0208876e2196136a09a8

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

utils/genrandconfig

@@ -200,6 +200,8 @@ def fixup_config(sysinfo, configfile):
     with open(configfile) as configf:
         configlines = configf.readlines()
 
+    ROOTFS_SIZE = '5G'
+
     BR2_TOOLCHAIN_EXTERNAL_URL = 'BR2_TOOLCHAIN_EXTERNAL_URL="http://autobuild.buildroot.org/toolchains/tarballs/'
 
     if "BR2_NEEDS_HOST_JAVA=y\n" in configlines and not sysinfo.has("java"):
@@ -441,6 +443,16 @@ def fixup_config(sysinfo, configfile):
         configlines.remove('BR2_TARGET_OPTEE_OS=y\n')
         configlines.remove('BR2_TARGET_OPTEE_OS_PLATFORM=""\n')
 
+    if 'BR2_TARGET_ROOTFS_EXT2_GEN=y\n' in configlines and \
+       'BR2_TARGET_ROOTFS_EXT2_SIZE="60M"\n' in configlines:
+        configlines.remove('BR2_TARGET_ROOTFS_EXT2_SIZE="60M"\n')
+        configlines.append('BR2_TARGET_ROOTFS_EXT2_SIZE="%s"\n' % ROOTFS_SIZE)
+
+    if 'BR2_TARGET_ROOTFS_F2FS=y\n' in configlines and \
+       'BR2_TARGET_ROOTFS_F2FS_SIZE="100M"\n' in configlines:
+        configlines.remove('BR2_TARGET_ROOTFS_F2FS_SIZE="100M"\n')
+        configlines.append('BR2_TARGET_ROOTFS_F2FS_SIZE="%s"\n' % ROOTFS_SIZE)
+
     if 'BR2_TARGET_S500_BOOTLOADER=y\n' in configlines and \
        'BR2_TARGET_S500_BOOTLOADER_BOARD=""\n' in configlines:
         configlines.remove('BR2_TARGET_S500_BOOTLOADER=y\n')